| Saturday, January 8 |
| Future Astro Dave Matranga is born in Orange, CA. |
| Wednesday, February 2 |
| Future Astro Adam Everett is born in Austell, GA. |
| Wednesday, March 30 |
| Future Astro Jeriome Robertson is born in San Jose, CA. |
| Wednesday, April 6 |
| » Major-league debuts: Jose Baez (Mariners) |
| Future Astro Barry Wesson is born in Tupelo, MS. |
| Thursday, April 7 |
| » Major-league debuts: Al Woods (Blue Jays) |
| Friday, April 8 |
| » Defeated Braves (0-1), 3-2 | Astrodome (1-0) | 1-0 | |
| » W: Ken Forsch (1-0) L: Bob Johnson (0-1) | Second | ½ out |
| » Major-league debuts: Julio Gonzalez (Astros) |
| Saturday, April 9 |
| » Defeated Braves (0-2), 2-0 | Astrodome (2-0) | 2-0 | Won 2 |
| » W: Joaquin Andujar (1-0) L: Phil Niekro (0-1) | First | -- |
| Sunday, April 10 |
| » Lost to Braves (1-2), 6-0 | Astrodome (2-1) | 2-1 | |
| » W: Dick Ruthven (1-0) L: Mark Lemongello (0-1) | First | -- |
| Monday, April 11 |
| » Defeated Reds (2-3), 4-3 | Astrodome (3-1) | 3-1 | |
| » W: Doug Konieczny (1-0) L: Woodie Fryman (1-1) S: Joe Niekro (1) | First | -- |
| Tuesday, April 12 |
| » Defeated Reds (2-4), 4-3 | Astrodome (4-1) | 4-1 | Won 2 |
| » W: J.R. Richard (1-0) L: Pat Zachry (0-1) S: Ken Forsch (1) | First | -- |
| Wednesday, April 13 |
| » Defeated Reds (2-5), 7-6 | Astrodome (5-1) | 5-1 | Won 3 |
| » W: Ken Forsch (2-0) L: Pedro Borbon (0-1) | First | -- |
| Friday, April 15 |
| » Lost to Braves (3-4), 4-3 | Atlanta-Fulton County Stadium (0-1) | 5-2 | |
| » W: Dick Ruthven (2-0) L: Mark Lemongello (0-2) S: Rick Camp (2) | First | -- |
| Saturday, April 16 |
| » Lost to Braves (4-4), 4-3 | Atlanta-Fulton County Stadium (0-2) | 5-3 | Lost 2 |
| » W: Andy Messersmith (1-1) L: Joe Sambito (0-1) | Second | 1 out |
| Sunday, April 17 |
| » Lost to Braves (5-4), 5-4 | Atlanta-Fulton County Stadium (0-3) | 5-4 | Lost 3 |
| » W: Mike Marshall (1-0) L: Ken Forsch (2-1) S: Rick Camp (3) | Second | 2 out |
| Tuesday, April 19 |
| » Lost to Giants (4-6), 7-4 | Astrodome (5-2) | 5-5 | Lost 4 |
| » W: Jim Barr (2-1) L: Floyd Bannister (0-1) S: Gary Lavelle (1) | Third | 3 out |
| » Major-league debuts: Floyd Bannister (Astros) |
| Wednesday, April 20 |
| » Lost to Giants (5-6), 1-0 | Astrodome (5-3) | 5-6 | Lost 5 |
| » W: Ed Halicki (2-1) L: Mark Lemongello (0-3) S: Gary Lavelle (2) | Third | 4 out |
| Friday, April 22 |
| » Lost to Padres (6-8), 4-2 | Astrodome (5-4) | 5-7 | Lost 6 |
| » W: Bob Shirley (2-1) L: J.R. Richard (1-1) S: Rollie Fingers (2) | Fourth | 4 out |
| Saturday, April 23 |
| » Lost to Padres (7-8), 7-2 | Astrodome (5-5) | 5-8 | Lost 7 |
| » W: Tom Griffin (1-0) L: Joaquin Andujar (1-1) S: Dave Tomlin (1) | Fifth | 5½ out |
| » Lost to Padres (8-8), 11-8 | Astrodome (5-6) | 5-9 | Lost 8 |
| » W: Victor Bernal (1-0) L: Dan Larson (0-1) S: Rollie Fingers (3) | Fifth | 5½ out |
| Sunday, April 24 |
| » Defeated Padres (8-9), 9-8 | Astrodome (6-6) | 6-9 | |
| » W: Joe Sambito (1-1) L: Rollie Fingers (2-1) | Fifth | 5½ out |
| Tuesday, April 26 |
| » Defeated Giants (7-8), 4-3 | Candlestick Park (1-0) | 7-9 | Won 2 |
| » W: Joe Sambito (2-1) L: Charlie Williams (0-1) | Fourth | 6 out |
| Wednesday, April 27 |
| » Lost to Giants (8-8), 3-2 | Candlestick Park (1-1) | 7-10 | |
| » W: Randy Moffitt (1-1) L: J.R. Richard (1-2) | Fourth | 7 out |
| Thursday, April 28 |
| » Defeated Giants (8-9), 3-1 | Candlestick Park (2-1) | 8-10 | |
| » W: Joaquin Andujar (2-1) L: John Montefusco (2-2) S: Ken Forsch (2) | Third | 7 out |
| Friday, April 29 |
| » Defeated Pirates (9-7), 11-3 | Three Rivers Stadium (1-0) | 9-10 | Won 2 |
| » W: Floyd Bannister (1-1) L: Jerry Reuss (0-3) | Second | 7 out |
| Saturday, April 30 |
| » Lost to Pirates (10-7), 10-0 | Three Rivers Stadium (1-1) | 9-11 | |
| » W: Jim Rooker (3-1) L: Doug Konieczny (1-1) | Third | 8 out |
| Sunday, May 1 |
| » Lost to Pirates (11-7), 4-3 | Three Rivers Stadium (1-2) | 9-12 | Lost 2 |
| » W: Rich Gossage (3-0) L: Ken Forsch (2-2) | Third | 8 out |
| Tuesday, May 3 |
| » Lost to Cubs (9-9), 9-0 | Wrigley Field (0-1) | 9-13 | Lost 3 |
| » W: Ray Burris (3-3) L: J.R. Richard (1-3) | Third | 9½ out |
| Wednesday, May 4 |
| » Defeated Cubs (9-10), 5-4 | Wrigley Field (1-1) | 10-13 | |
| » W: Ken Forsch (3-2) L: Bruce Sutter (0-1) S: Bo McLaughlin (1) | Third | 9½ out |
| Thursday, May 5 |
| » Lost to Cubs (10-10), 8-7 | Wrigley Field (1-2) | 10-14 | |
| » W: Rick Reuschel (4-1) L: Floyd Bannister (1-2) S: Bruce Sutter (5) | Third | 10½ out |
| Friday, May 6 |
| » Lost to Cardinals (15-8), 4-1 | Busch Stadium II (0-1) | 10-15 | Lost 2 |
| » W: Pete Falcone (1-3) L: Bo McLaughlin (0-1) S: Al Hrabosky (3) | Fourth | 11½ out |
| Saturday, May 7 |
| » Defeated Cardinals (15-9), 3-1 | Busch Stadium II (1-1) | 11-15 | |
| » W: Joe Sambito (3-1) L: John Urrea (1-2) | Second | 10½ out |
| Sunday, May 8 |
| » Lost to Cardinals (16-9), 2-1 | Busch Stadium II (1-2) | 11-16 | |
| » W: Buddy Schultz (1-0) L: Mark Lemongello (0-4) S: Clay Carroll (1) | Third | 11 out |
| Monday, May 9 |
| » Lost to Cubs (14-10), 6-1 | Astrodome (6-7) | 11-17 | Lost 2 |
| » W: Rick Reuschel (5-1) L: Joaquin Andujar (2-2) S: Guillermo Hernandez (1) | Third | 11½ out |
| Tuesday, May 10 |
| » Lost to Cubs (15-10), 11-5 | Astrodome (6-8) | 11-18 | Lost 3 |
| » W: Mike Krukow (2-2) L: Floyd Bannister (1-3) | Fourth | 11½ out |
| Wednesday, May 11 |
| » Defeated Cubs (15-11), 8-2 | Astrodome (7-8) | 12-18 | |
| » W: J.R. Richard (2-3) L: Ray Burris (4-4) | Fifth | 11½ out |
| Friday, May 13 |
| » Defeated Pirates (20-9), 3-0 | Astrodome (8-8) | 13-18 | Won 2 |
| » W: Mark Lemongello (1-4) L: Jerry Reuss (0-4) S: Ken Forsch (3) | Third | 11 out |
| Saturday, May 14 |
| » Lost to Pirates (21-9), 6-2 | Astrodome (8-9) | 13-19 | |
| » W: Larry Demery (3-1) L: Joaquin Andujar (2-3) S: Rich Gossage (7) | Fourth | 12 out |
| Sunday, May 15 |
| » Lost to Pirates (22-9), 3-1 | Astrodome (8-10) | 13-20 | Lost 2 |
| » W: Kent Tekulve (3-0) L: J.R. Richard (2-4) | Fourth | 13 out |
| Tuesday, May 17 |
| » Defeated Cardinals (20-13), 5-2 | Astrodome (9-10) | 14-20 | |
| » W: Ken Forsch (4-2) L: Eric Rasmussen (2-5) | Third | 12½ out |
| Wednesday, May 18 |
| » Lost to Cardinals (21-13), 8-4 | Astrodome (9-11) | 14-21 | |
| » W: Buddy Schultz (3-0) L: Mark Lemongello (1-5) | Third | 13½ out |
| Thursday, May 19 |
| » Defeated Phillies (17-16), 3-2 | Astrodome (10-11) | 15-21 | |
| » W: Joaquin Andujar (3-3) L: Gene Garber (1-3) S: Joe Sambito (1) | Third | 12½ out |
| Friday, May 20 |
| » Defeated Phillies (17-17), 5-2 | Astrodome (11-11) | 16-21 | Won 2 |
| » W: J.R. Richard (3-4) L: Steve Carlton (5-2) | Third | 12½ out |
| Saturday, May 21 |
| » Lost to Phillies (18-17), 7-4 | Astrodome (11-12) | 16-22 | |
| » W: Ron Reed (2-1) L: Dan Larson (0-2) | Third | 13½ out |
| Sunday, May 22 |
| » Lost to Phillies (19-17), 6-3 | Astrodome (11-13) | 16-23 | Lost 2 |
| » W: Larry Christenson (4-4) L: Floyd Bannister (1-4) S: Warren Brusstar (1) | Third | 13½ out |
| Tuesday, May 24 |
| » Lost to Dodgers (31-10), 4-2 | Dodger Stadium (0-1) | 16-24 | Lost 3 |
| » W: Rick Rhoden (7-1) L: Mark Lemongello (1-6) S: Charlie Hough (12) | Fifth | 14½ out |
| Wednesday, May 25 |
| » Defeated Dodgers (31-11), 7-6 | Dodger Stadium (1-1) | 17-24 | |
| » W: Joaquin Andujar (4-3) L: Charlie Hough (3-3) S: Ken Forsch (4) | Fifth | 13½ out |
| Thursday, May 26 |
| » Lost to Dodgers (32-11), 4-3 | Dodger Stadium (1-2) | 17-25 | |
| » W: Mike Garman (2-0) L: Ken Forsch (4-3) | Fifth | 14½ out |
| Friday, May 27 |
| » Defeated Padres (19-28), 4-3 | San Diego/Jack Murphy Stadium (1-0) | 18-25 | |
| » W: Bo McLaughlin (1-1) L: Rick Sawyer (3-4) S: Ken Forsch (5) | Fourth | 14½ out |
| Saturday, May 28 |
| » Lost to Padres (20-28), 6-5 | San Diego/Jack Murphy Stadium (1-1) | 18-26 | |
| » W: Bob Shirley (4-5) L: Floyd Bannister (1-5) S: Rollie Fingers (9) | Fifth | 14½ out |
| Sunday, May 29 |
| » Lost to Padres (21-28), 3-2 | San Diego/Jack Murphy Stadium (1-2) | 18-27 | Lost 2 |
| » W: Dan Spillner (2-0) L: Mark Lemongello (1-7) S: Rollie Fingers (10) | Fifth | 14½ out |
| Monday, May 30 |
| » Defeated Dodgers (33-14), 5-3 | Astrodome (12-13) | 19-27 | |
| » W: Joaquin Andujar (5-3) L: Doug Rau (5-1) S: Ken Forsch (6) | Fifth | 13½ out |
| Tuesday, May 31 |
| » Defeated Dodgers (33-15), 5-2 | Astrodome (13-13) | 20-27 | Won 2 |
| » W: J.R. Richard (4-4) L: Burt Hooton (4-2) | Fifth | 12½ out |
| Wednesday, June 1 |
| » Lost to Dodgers (34-15), 6-2 | Astrodome (13-14) | 20-28 | |
| » W: Tommy John (6-2) L: Bo McLaughlin (1-2) S: Charlie Hough (14) | Fifth | 13½ out |
| Thursday, June 2 |
| » Defeated Reds (23-24), 6-4 | Riverfront Stadium (1-0) | 21-28 | |
| » W: Gene Pentz (1-0) L: Dale Murray (3-2) S: Ken Forsch (7) | Fifth | 13 out |
| Friday, June 3 |
| » Lost to Reds (24-24), 4-0 | Riverfront Stadium (1-1) | 21-29 | |
| » W: Fred Norman (5-2) L: Mark Lemongello (1-8) | Fifth | 13 out |
| Saturday, June 4 |
| » Defeated Reds (24-25), 8-1 | Riverfront Stadium (2-1) | 22-29 | |
| » W: Joaquin Andujar (6-3) L: Tom Hume (0-2) | Fourth | 13 out |
| Sunday, June 5 |
| » Lost to Reds (25-25), 14-4 | Riverfront Stadium (2-2) | 22-30 | |
| » W: Gary Nolan (4-0) L: J.R. Richard (4-5) | Fifth | 14 out |
| Monday, June 6 |
| » Lost to Phillies (27-23), 9-5 | Veteran's Stadium (0-1) | 22-31 | Lost 2 |
| » W: Larry Christenson (5-5) L: Bo McLaughlin (1-3) S: Warren Brusstar (2) | Fifth | 14 out |
| Tuesday, June 7 |
| » Lost to Phillies (28-23), 9-8 | Veteran's Stadium (0-2) | 22-32 | Lost 3 |
| » W: Tom Underwood (3-1) L: Joe Niekro (0-1) S: Gene Garber (6) | Fifth | 14 out |
| Wednesday, June 8 |
| » Lost to Phillies (29-23), 3-2 | Veteran's Stadium (0-3) | 22-33 | Lost 4 |
| » W: Steve Carlton (8-3) L: Mark Lemongello (1-9) | Fifth | 15 out |
| Friday, June 10 |
| » Defeated Mets (22-33), 4-1 | Astrodome (14-14) | 23-33 | |
| » W: Joaquin Andujar (7-3) L: Jon Matlack (3-8) | Fifth | 13½ out |
| Former Astro Dick Farrell dies in Great Yarmouth, England at the age of 44. |
| Saturday, June 11 |
| » Defeated Mets (22-34), 4-1 | Astrodome (15-14) | 24-33 | Won 2 |
| » W: J.R. Richard (5-5) L: Craig Swan (3-5) | Fifth | 14 out |
| » Lost to Mets (23-34), 6-4 | Astrodome (15-15) | 24-34 | |
| » W: Skip Lockwood (1-3) L: Ken Forsch (4-4) | Fifth | 14 out |
| Sunday, June 12 |
| » Lost to Mets (24-34), 3-1 | Astrodome (15-16) | 24-35 | Lost 2 |
| » W: Tom Seaver (7-3) L: Floyd Bannister (1-6) | Fifth | 14 out |
| Monday, June 13 |
| » Lost to Expos (25-31), 3-2 | Astrodome (15-17) | 24-36 | Lost 3 |
| » W: Santo Alcala (2-3) L: Mark Lemongello (1-10) S: Joe Kerrigan (5) | Fifth | 14½ out |
| Tuesday, June 14 |
| » Defeated Expos (25-32), 5-0 | Astrodome (16-17) | 25-36 | |
| » W: Joaquin Andujar (8-3) L: Stan Bahnsen (2-4) S: Joe Niekro (2) | Fifth | 14½ out |
| Wednesday, June 15 |
| » Lost to Expos (26-32), 2-0 | Astrodome (16-18) | 25-37 | |
| » W: Jackie Brown (4-4) L: J.R. Richard (5-6) | Fifth | 15½ out |
| Thursday, June 16 |
| » Lost to Mets (27-35), 4-3 | Shea Stadium (0-1) | 25-38 | Lost 2 |
| » W: Nino Espinosa (4-4) L: Joe Sambito (3-2) S: Skip Lockwood (10) | Fifth | 16½ out |
| » Major-league debuts: Steve Henderson (Mets) |
| Friday, June 17 |
| » Defeated Mets (27-36), 7-1 | Shea Stadium (1-1) | 26-38 | |
| » W: Floyd Bannister (2-6) L: Pat Zachry (3-8) | Fifth | 15½ out |
| Saturday, June 18 |
| » Defeated Mets (27-37), 4-3 | Shea Stadium (2-1) | 27-38 | Won 2 |
| » W: Gene Pentz (2-0) L: Jerry Koosman (5-7) S: Joe Niekro (3) | Fifth | 15½ out |
| Sunday, June 19 |
| » Lost to Mets (28-37), 8-2 | Shea Stadium (2-2) | 27-39 | |
| » W: Craig Swan (4-5) L: Joaquin Andujar (8-4) | Fifth | 16½ out |
| Monday, June 20 |
| » Defeated Expos (27-35), 6-3 | Stade Olympique (1-0) | 28-39 | |
| » W: J.R. Richard (6-6) L: Jackie Brown (4-5) | Fifth | 16½ out |
| Tuesday, June 21 |
| » Lost to Expos (28-35), 6-0 | Stade Olympique (1-1) | 28-40 | |
| » W: Steve Rogers (9-5) L: Ken Forsch (4-5) | Fifth | 16½ out |
| Wednesday, June 22 |
| » Defeated Expos (28-36), 7-0 | Stade Olympique (2-1) | 29-40 | |
| » W: Floyd Bannister (3-6) L: Santo Alcala (2-5) | Fifth | 16½ out |
| Friday, June 24 |
| » Defeated Giants (32-39), 6-5 | Astrodome (17-18) | 30-40 | Won 2 |
| » W: Joe Sambito (4-2) L: Tommy Toms (0-1) | Fourth | 16½ out |
| Saturday, June 25 |
| » Defeated Giants (32-40), 4-3 | Astrodome (18-18) | 31-40 | Won 3 |
| » W: Joe Niekro (1-1) L: Randy Moffitt (2-5) | Fourth | 16 out |
| » Lost to Giants (33-40), 4-1 | Astrodome (18-19) | 31-41 | |
| » W: Charlie Williams (3-1) L: Mark Lemongello (1-11) S: Gary Lavelle (10) | Fourth | 16 out |
| Sunday, June 26 |
| » Lost to Giants (34-40), 2-0 | Astrodome (18-20) | 31-42 | Lost 2 |
| » W: Ed Halicki (7-6) L: Ken Forsch (4-6) | Fourth | 16½ out |
| Monday, June 27 |
| » Defeated Padres (31-45), 7-6 | Astrodome (19-20) | 32-42 | |
| » W: Joe Niekro (2-1) L: Rollie Fingers (4-4) | Fourth | 16½ out |
| Tuesday, June 28 |
| » Defeated Padres (31-46), 5-1 | Astrodome (20-20) | 33-42 | Won 2 |
| » W: Joaquin Andujar (9-4) L: Bob Owchinko (2-2) | Fourth | 16½ out |
| Wednesday, June 29 |
| » Lost to Padres (32-46), 7-4 | Astrodome (20-21) | 33-43 | |
| » W: Dave Freisleben (1-5) L: Dan Larson (0-3) S: Dan Spillner (3) | Fourth | 17½ out |
| Future Astro Tony McKnight is born in Texarkana, AR. |
| Friday, July 1 |
| » Defeated Braves (28-48), 3-1 | Astrodome (21-21) | 34-43 | |
| » W: J.R. Richard (7-6) L: Don Collins (1-7) S: Joe Niekro (4) | Fourth | 17 out |
| Saturday, July 2 |
| » Lost to Braves (29-48), 2-1 | Astrodome (21-22) | 34-44 | |
| » W: Max Leon (3-3) L: Joe Niekro (2-2) S: Steve Kline (1) | Fourth | 18 out |
| Sunday, July 3 |
| » Defeated Braves (29-49), 9-3 | Astrodome (22-22) | 35-44 | |
| » W: Floyd Bannister (4-6) L: Frank LaCorte (1-8) | Third | 18 out |
| Monday, July 4 |
| » Defeated Padres (33-49), 12-7 | San Diego/Jack Murphy Stadium (2-2) | 36-44 | Won 2 |
| » W: Joe Niekro (3-2) L: Tom Griffin (5-6) | Third | 18 out |
| Tuesday, July 5 |
| » Lost to Padres (34-49), 8-7 | San Diego/Jack Murphy Stadium (2-3) | 36-45 | |
| » W: Rollie Fingers (5-4) L: Joe Niekro (3-3) | Third | 18½ out |
| Wednesday, July 6 |
| » Defeated Dodgers (54-27), 2-1 | Dodger Stadium (2-2) | 37-45 | |
| » W: Bo McLaughlin (2-3) L: Mike Garman (4-1) | Third | 17½ out |
| Thursday, July 7 |
| » Lost to Dodgers (55-27), 7-4 | Dodger Stadium (2-3) | 37-46 | |
| » W: Doug Rau (9-1) L: Ken Forsch (4-7) S: Charlie Hough (19) | Third | 18½ out |
| Friday, July 8 |
| » Lost to Reds (45-35), 8-5 | Astrodome (22-23) | 37-47 | Lost 2 |
| » W: Doug Capilla (2-0) L: Floyd Bannister (4-7) S: Dale Murray (3) | Third | 19½ out |
| Saturday, July 9 |
| » Lost to Reds (46-35), 3-1 | Astrodome (22-24) | 37-48 | Lost 3 |
| » W: Tom Seaver (9-5) L: Joaquin Andujar (9-5) | Fourth | 19½ out |
| Sunday, July 10 |
| » Defeated Reds (46-36), 6-5 | Astrodome (23-24) | 38-48 | |
| » W: Joe Niekro (4-3) L: Pedro Borbon (5-4) S: Bo McLaughlin (2) | Fourth | 18 out |
| Monday, July 11 |
| » Defeated Reds (46-37), 2-0 | Astrodome (24-24) | 39-48 | Won 2 |
| » W: J.R. Richard (8-6) L: Fred Norman (9-4) | Fourth | 17½ out |
| Tuesday, July 12 |
| » Lost to Dodgers (57-30), 8-0 | Astrodome (24-25) | 39-49 | |
| » W: Doug Rau (10-1) L: Joe Sambito (4-3) | Fourth | 18½ out |
| » Major-league debuts: Terry Puhl (Astros) |
| Wednesday, July 13 |
| » Defeated Dodgers (57-31), 3-2 | Astrodome (25-25) | 40-49 | |
| » W: Bo McLaughlin (3-3) L: Elias Sosa (0-2) | Fourth | 17½ out |
| Thursday, July 14 |
| » Defeated Dodgers (57-32), 4-3 | Astrodome (26-25) | 41-49 | Won 2 |
| » W: Joaquin Andujar (10-5) L: Don Sutton (10-4) S: Bo McLaughlin (3) | Fourth | 16½ out |
| Friday, July 15 |
| » Lost to Reds (48-39), 8-3 | Riverfront Stadium (2-3) | 41-50 | |
| » W: Paul Moskau (1-1) L: Gene Pentz (2-1) | Fourth | 16½ out |
| Saturday, July 16 |
| » Defeated Reds (48-40), 8-0 | Riverfront Stadium (3-3) | 42-50 | |
| » W: J.R. Richard (9-6) L: Fred Norman (9-5) S: Joe Sambito (2) | Fourth | 16½ out |
| Sunday, July 17 |
| » Defeated Reds (48-41), 3-1 | Riverfront Stadium (4-3) | 43-50 | Won 2 |
| » W: Mark Lemongello (2-11) L: Doug Capilla (2-1) S: Joe Niekro (5) | Third | 16½ out |
| Thursday, July 21 |
| » Lost to Cardinals (48-45), 4-0 | Busch Stadium II (1-3) | 43-51 | |
| » W: Bob Forsch (12-4) L: J.R. Richard (9-7) | Third | 16½ out |
| Friday, July 22 |
| » Defeated Cardinals (48-46), 4-2 | Busch Stadium II (2-3) | 44-51 | |
| » W: Mark Lemongello (3-11) L: Clay Carroll (4-2) | Third | 15½ out |
| Saturday, July 23 |
| » Lost to Cardinals (49-46), 4-3 | Busch Stadium II (2-4) | 44-52 | |
| » W: Rawly Eastwick (5-6) L: Bo McLaughlin (3-4) | Third | 15½ out |
| Sunday, July 24 |
| » Defeated Cubs (56-37), 10-6 | Wrigley Field (2-2) | 45-52 | |
| » W: Gene Pentz (3-1) L: Ray Burris (10-10) S: Joe Sambito (3) | Third | 15 out |
| » Defeated Cubs (56-38), 6-4 | Wrigley Field (3-2) | 46-52 | Won 2 |
| » W: Joe Niekro (5-3) L: Donnie Moore (3-1) | Third | 15 out |
| Monday, July 25 |
| » Lost to Cubs (57-38), 9-7 | Wrigley Field (3-3) | 46-53 | |
| » W: Guillermo Hernandez (4-3) L: Mark Lemongello (3-12) | Third | 15 out |
| Tuesday, July 26 |
| » Lost to Pirates (56-42), 3-2 | Three Rivers Stadium (1-3) | 46-54 | Lost 2 |
| » W: John Candelaria (11-3) L: J.R. Richard (9-8) S: Rich Gossage (17) | Third | 15½ out |
| Wednesday, July 27 |
| » Lost to Pirates (57-42), 3-2 | Three Rivers Stadium (1-4) | 46-55 | Lost 3 |
| » W: Kent Tekulve (9-1) L: Bo McLaughlin (3-5) | Third | 16½ out |
| Thursday, July 28 |
| » Lost to Pirates (58-42), 9-4 | Three Rivers Stadium (1-5) | 46-56 | Lost 4 |
| » W: Jim Rooker (9-5) L: Dan Larson (0-4) | Third | 17½ out |
| Friday, July 29 |
| » Defeated Cubs (60-40), 1-0 | Astrodome (27-25) | 47-56 | |
| » W: Joe Niekro (6-3) L: Bill Bonham (9-10) | Third | 17½ out |
| Saturday, July 30 |
| » Defeated Cubs (60-41), 11-3 | Astrodome (28-25) | 48-56 | Won 2 |
| » W: Joe Sambito (5-3) L: Paul Reuschel (4-3) | Third | 17½ out |
| » Major-league debuts: Tom Dixon (Astros) |
| Sunday, July 31 |
| » Lost to Cubs (61-41), 4-1 | Astrodome (28-26) | 48-57 | |
| » W: Ray Burris (11-10) L: J.R. Richard (9-9) | Third | 18½ out |
| Monday, August 1 |
| » Defeated Pirates (59-45), 4-3 | Astrodome (29-26) | 49-57 | |
| » W: Mark Lemongello (4-12) L: Rich Gossage (8-7) | Third | 17½ out |
| Tuesday, August 2 |
| » Lost to Pirates (60-45), 6-3 | Astrodome (29-27) | 49-58 | |
| » W: Grant Jackson (3-3) L: Dan Larson (0-5) | Third | 18½ out |
| Wednesday, August 3 |
| » Defeated Pirates (60-46), 3-0 | Astrodome (30-27) | 50-58 | |
| » W: Joe Niekro (7-3) L: Bruce Kison (6-6) | Third | 17½ out |
| Friday, August 5 |
| » Defeated Cardinals (59-49), 5-4 | Astrodome (31-27) | 51-58 | Won 2 |
| » W: J.R. Richard (10-9) L: John Denny (7-3) S: Joe Sambito (4) | Third | 16½ out |
| Saturday, August 6 |
| » Lost to Cardinals (60-49), 3-1 | Astrodome (31-28) | 51-59 | |
| » W: Bob Forsch (14-5) L: Mark Lemongello (4-13) S: Butch Metzger (4) | Third | 16 out |
| » Defeated Cardinals (60-50), 4-1 | Astrodome (32-28) | 52-59 | |
| » W: Tom Dixon (1-0) L: Tom Underwood (6-7) | Third | 16 out |
| Sunday, August 7 |
| » Lost to Cardinals (61-50), 5-2 | Astrodome (32-29) | 52-60 | |
| » W: John Urrea (4-3) L: Dan Larson (0-6) S: Butch Metzger (5) | Third | 16 out |
| Tuesday, August 9 |
| » Lost to Giants (51-61), 4-3 | Candlestick Park (2-2) | 52-61 | Lost 2 |
| » W: Jim Barr (11-8) L: Joe Niekro (7-4) S: Gary Lavelle (16) | Fourth | 17 out |
| » Lost to Giants (52-61), 5-0 | Candlestick Park (2-3) | 52-62 | Lost 3 |
| » W: Bob Knepper (5-6) L: Gene Pentz (3-2) | Fourth | 17 out |
| Wednesday, August 10 |
| » Defeated Giants (52-62), 8-6 | Candlestick Park (3-3) | 53-62 | |
| » W: J.R. Richard (11-9) L: Lynn McGlothen (2-9) S: Ken Forsch (8) | Third | 17 out |
| Thursday, August 11 |
| » Defeated Giants (52-63), 7-5 | Candlestick Park (4-3) | 54-62 | Won 2 |
| » W: Dan Larson (1-6) L: Gary Lavelle (6-7) S: Joe Sambito (5) | Third | 16 out |
| Friday, August 12 |
| » Lost to Padres (53-67), 5-4 | San Diego/Jack Murphy Stadium (2-4) | 54-63 | |
| » W: Rollie Fingers (8-4) L: Ken Forsch (4-8) | Third | 16 out |
| Sunday, August 14 |
| » Defeated Padres (53-68), 6-3 | San Diego/Jack Murphy Stadium (3-4) | 55-63 | |
| » W: Joe Niekro (8-4) L: Dave Freisleben (5-6) | Third | 16½ out |
| Monday, August 15 |
| » Defeated Braves (41-75), 15-3 | Atlanta-Fulton County Stadium (1-3) | 56-63 | Won 2 |
| » W: J.R. Richard (12-9) L: Buzz Capra (2-9) S: Dan Larson (1) | Third | 15½ out |
| Tuesday, August 16 |
| » Defeated Braves (41-76), 4-1 | Atlanta-Fulton County Stadium (2-3) | 57-63 | Won 3 |
| » W: Mark Lemongello (5-13) L: Dick Ruthven (4-9) S: Bo McLaughlin (4) | Third | 15½ out |
| Wednesday, August 17 |
| » Lost to Braves (42-76), 9-6 | Atlanta-Fulton County Stadium (2-4) | 57-64 | |
| » W: Don Collins (2-9) L: Joe Sambito (5-4) S: Dave Campbell (3) | Third | 16 out |
| Friday, August 19 |
| » Lost to Phillies (74-45), 9-5 | Veteran's Stadium (0-4) | 57-65 | Lost 2 |
| » W: Larry Christenson (12-5) L: Joe Niekro (8-5) | Third | 16½ out |
| Saturday, August 20 |
| » Lost to Phillies (75-45), 5-4 | Veteran's Stadium (0-5) | 57-66 | Lost 3 |
| » W: Tug McGraw (7-2) L: Bo McLaughlin (3-6) | Third | 16½ out |
| Sunday, August 21 |
| » Lost to Phillies (76-45), 7-3 | Veteran's Stadium (0-6) | 57-67 | Lost 4 |
| » W: Steve Carlton (18-7) L: Mark Lemongello (5-14) | Third | 17½ out |
| Monday, August 22 |
| » Lost to Mets (50-74), 2-1 | Shea Stadium (2-3) | 57-68 | Lost 5 |
| » W: Pat Zachry (7-12) L: J.R. Richard (12-10) S: Skip Lockwood (18) | Third | 17½ out |
| Tuesday, August 23 |
| » Lost to Mets (51-74), 2-1 | Shea Stadium (2-4) | 57-69 | Lost 6 |
| » W: Skip Lockwood (3-6) L: Joe Sambito (5-5) | Fourth | 17½ out |
| Wednesday, August 24 |
| » Defeated Phillies (78-46), 3-1 | Astrodome (33-29) | 58-69 | |
| » W: Joe Niekro (9-5) L: Larry Christenson (12-6) | Third | 17½ out |
| Thursday, August 25 |
| » Defeated Phillies (78-47), 6-5 | Astrodome (34-29) | 59-69 | Won 2 |
| » W: Gene Pentz (4-2) L: Ron Reed (7-5) S: Bo McLaughlin (5) | Third | 16½ out |
| Friday, August 26 |
| » Defeated Expos (59-68), 6-5 | Astrodome (35-29) | 60-69 | Won 3 |
| » W: Bo McLaughlin (4-6) L: Don Stanhouse (9-10) | Third | 16½ out |
| Saturday, August 27 |
| » Defeated Expos (59-69), 4-0 | Astrodome (36-29) | 61-69 | Won 4 |
| » W: J.R. Richard (13-10) L: Stan Bahnsen (8-8) | Third | 16½ out |
| Sunday, August 28 |
| » Defeated Expos (59-70), 7-2 | Astrodome (37-29) | 62-69 | Won 5 |
| » W: Floyd Bannister (5-7) L: Steve Rogers (14-13) | Third | 16½ out |
| Monday, August 29 |
| Future Astro Roy Oswalt is born in Kosciusko, MS. |
| Tuesday, August 30 |
| » Defeated Mets (51-80), 6-2 | Astrodome (38-29) | 63-69 | Won 6 |
| » W: Joe Niekro (10-5) L: Bob Myrick (1-2) | Third | 16 out |
| Wednesday, August 31 |
| » Defeated Mets (51-81), 5-2 | Astrodome (39-29) | 64-69 | Won 7 |
| » W: Mark Lemongello (6-14) L: Jerry Koosman (8-18) | Third | 16 out |
| Friday, September 2 |
| » Defeated Expos (60-73), 5-2 | Stade Olympique (3-1) | 65-69 | Won 8 |
| » W: J.R. Richard (14-10) L: Stan Bahnsen (8-9) | Third | 16 out |
| Saturday, September 3 |
| » Lost to Expos (61-73), 5-1 | Stade Olympique (3-2) | 65-70 | |
| » W: Steve Rogers (15-13) L: Floyd Bannister (5-8) | Third | 17 out |
| » Major-league debuts: Mike Fischlin (Astros) |
| Sunday, September 4 |
| » Defeated Expos (61-74), 7-1 | Stade Olympique (4-2) | 66-70 | |
| » W: Joe Niekro (11-5) L: Jackie Brown (9-12) | Third | 17 out |
| » Major-league debuts: Dan Schatzeder (Expos) |
| Monday, September 5 |
| » Defeated Reds (73-65), 5-1 | Astrodome (40-29) | 67-70 | Won 2 |
| » W: Mark Lemongello (7-14) L: Tom Seaver (16-6) | Third | 16 out |
| Tuesday, September 6 |
| » Defeated Reds (73-66), 8-3 | Astrodome (41-29) | 68-70 | Won 3 |
| » W: Joaquin Andujar (11-5) L: Doug Capilla (6-7) S: Joe Sambito (6) | Third | 16 out |
| Wednesday, September 7 |
| » Lost to Padres (63-78), 9-5 | Astrodome (41-30) | 68-71 | |
| » W: Dave Freisleben (7-7) L: J.R. Richard (14-11) S: Rollie Fingers (32) | Third | 17 out |
| Thursday, September 8 |
| » Defeated Padres (63-79), 7-1 | Astrodome (42-30) | 69-71 | |
| » W: Floyd Bannister (6-8) L: Bob Shirley (9-17) | Third | 17 out |
| Friday, September 9 |
| » Defeated Giants (65-77), 6-1 | Astrodome (43-30) | 70-71 | Won 2 |
| » W: Joe Niekro (12-5) L: Jim Barr (12-14) | Third | 17 out |
| Saturday, September 10 |
| » Defeated Giants (65-78), 2-0 | Astrodome (44-30) | 71-71 | Won 3 |
| » W: Mark Lemongello (8-14) L: Bob Knepper (8-8) S: Joe Sambito (7) | Third | 16 out |
| Sunday, September 11 |
| » Lost to Giants (66-78), 2-1 | Astrodome (44-31) | 71-72 | |
| » W: Ed Halicki (14-10) L: Joaquin Andujar (11-6) S: Gary Lavelle (19) | Third | 16 out |
| Monday, September 12 |
| » Defeated Reds (76-69), 7-2 | Riverfront Stadium (5-3) | 72-72 | |
| » W: J.R. Richard (15-11) L: Mario Soto (2-6) | Third | 16 out |
| » Major-league debuts: Angel Torres (Reds) |
| Tuesday, September 13 |
| » Defeated Reds (76-70), 13-4 | Riverfront Stadium (6-3) | 73-72 | Won 2 |
| » W: Floyd Bannister (7-8) L: Paul Moskau (4-6) S: Gene Pentz (1) | Third | 16 out |
| Wednesday, September 14 |
| » Lost to Giants (68-79), 3-2 | Candlestick Park (4-4) | 73-73 | |
| » W: Bob Knepper (9-8) L: Joe Niekro (12-6) S: Jack Curtis (1) | Third | 16 out |
| Thursday, September 15 |
| » Defeated Giants (68-80), 6-3 | Candlestick Park (5-4) | 74-73 | |
| » W: Gene Pentz (5-2) L: Ed Halicki (14-11) | Third | 15 out |
| Friday, September 16 |
| » Lost to Padres (65-85), 4-3 | San Diego/Jack Murphy Stadium (3-5) | 74-74 | |
| » W: Dave Tomlin (4-4) L: Joe Niekro (12-7) | Third | 16 out |
| Saturday, September 17 |
| » Defeated Padres (65-86), 11-0 | San Diego/Jack Murphy Stadium (4-5) | 75-74 | |
| » W: J.R. Richard (16-11) L: Dave Freisleben (7-8) | Third | 16 out |
| Tuesday, September 20 |
| » Defeated Braves (57-94), 6-3 | Astrodome (45-31) | 76-74 | Won 2 |
| » W: Joe Niekro (13-7) L: Dick Ruthven (7-11) | Third | 15½ out |
| Wednesday, September 21 |
| » Lost to Braves (58-94), 5-3 | Astrodome (45-32) | 76-75 | |
| » W: Phil Niekro (16-18) L: Joaquin Andujar (11-7) | Third | 15½ out |
| » Major-league debuts: Roy Thomas (Astros) |
| Thursday, September 22 |
| » Lost to Braves (59-94), 8-4 | Astrodome (45-33) | 76-76 | Lost 2 |
| » W: Eddie Solomon (6-6) L: J.R. Richard (16-12) S: Dave Campbell (11) | Third | 16 out |
| » Major-league debuts: Luis Pujols (Astros) |
| F |