| Tuesday, March 11 |
| Future Astro Chris Burke is born in Louisville, KY. |
| Thursday, April 10 |
| » Defeated Dodgers (0-1), 3-2 | Astrodome (1-0) | 1-0 | |
| » W: J.R. Richard (1-0) L: Burt Hooton (0-1) S: Joe Sambito (1) | First | -- |
| Friday, April 11 |
| » Defeated Dodgers (0-2), 10-6 | Astrodome (2-0) | 2-0 | Won 2 |
| » W: Dave Smith (1-0) L: Don Stanhouse (0-1) | First | -- |
| » Major-league debuts: Dave Smith (Astros) Steve Howe (Dodgers) |
| Saturday, April 12 |
| » Lost to Dodgers (1-2), 6-5 | Astrodome (2-1) | 2-1 | |
| » W: Steve Howe (1-0) L: Dave Smith (1-1) S: Burt Hooton (1) | Second | 1 out |
| Sunday, April 13 |
| » Defeated Dodgers (1-3), 4-2 | Astrodome (3-1) | 3-1 | |
| » W: Ken Forsch (1-0) L: Dave Goltz (0-1) S: Frank LaCorte (1) | Second | 1 out |
| Monday, April 14 |
| » Defeated Braves (0-5), 5-4 | Astrodome (4-1) | 4-1 | Won 2 |
| » W: Joe Sambito (1-0) L: Gene Garber (0-1) | Second | 1 out |
| Tuesday, April 15 |
| » Defeated Braves (0-6), 6-2 | Astrodome (5-1) | 5-1 | Won 3 |
| » W: Joe Niekro (1-0) L: Larry McWilliams (0-2) | Second | 1 out |
| Thursday, April 17 |
| » Lost to Dodgers (3-5), 6-4 | Dodger Stadium (0-1) | 5-2 | |
| » W: Jerry Reuss (1-0) L: Dave Smith (1-2) | Second | 2½ out |
| Friday, April 18 |
| » Defeated Dodgers (3-6), 7-4 | Dodger Stadium (1-1) | 6-2 | |
| » W: Ken Forsch (2-0) L: Dave Goltz (0-2) S: Joaquin Andujar (1) | Second | 1½ out |
| Saturday, April 19 |
| » Defeated Dodgers (3-7), 2-0 | Dodger Stadium (2-1) | 7-2 | Won 2 |
| » W: J.R. Richard (2-0) L: Bob Welch (0-1) | Second | 1½ out |
| Sunday, April 20 |
| » Lost to Dodgers (4-7), 4-2 | Dodger Stadium (2-2) | 7-3 | |
| » W: Jerry Reuss (2-0) L: Joe Niekro (1-1) | Second | 2½ out |
| » Major-league debuts: Mike Scioscia (Dodgers) |
| Monday, April 21 |
| » Lost to Reds (11-1), 6-5 | Astrodome (5-2) | 7-4 | Lost 2 |
| » W: Mike LaCoss (3-0) L: Vern Ruhle (0-1) S: Tom Hume (3) | Second | 3½ out |
| Tuesday, April 22 |
| » Defeated Reds (11-2), 8-0 | Astrodome (6-2) | 8-4 | |
| » W: Nolan Ryan (1-0) L: Frank Pastore (2-1) | Second | 2½ out |
| Future Astro Carlos Hernandez is born in Guacara, Venezuela. |
| Wednesday, April 23 |
| » Lost to Reds (12-2), 3-2 | Astrodome (6-3) | 8-5 | |
| » W: Tom Hume (2-0) L: Joaquin Andujar (0-1) S: Doug Bair (1) | Second | 3½ out |
| Friday, April 25 |
| » Defeated Mets (5-8), 7-4 | Astrodome (7-3) | 9-5 | |
| » W: J.R. Richard (3-0) L: Pete Falcone (1-1) | Second | 2½ out |
| Saturday, April 26 |
| » Defeated Mets (5-9), 6-0 | Astrodome (8-3) | 10-5 | Won 2 |
| » W: Joe Niekro (2-1) L: Ed Glynn (0-1) S: Frank LaCorte (2) | Second | 1½ out |
| Sunday, April 27 |
| » Defeated Mets (5-10), 4-3 | Astrodome (9-3) | 11-5 | Won 3 |
| » W: Frank LaCorte (1-0) L: Neil Allen (0-3) | Second | 1½ out |
| Tuesday, April 29 |
| » Defeated Reds (13-5), 3-0 | Riverfront Stadium (1-0) | 12-5 | Won 4 |
| » W: Ken Forsch (3-0) L: Charlie Leibrandt (1-2) | Second | ½ out |
| Wednesday, April 30 |
| » Defeated Reds (13-6), 5-1 | Riverfront Stadium (2-0) | 13-5 | Won 5 |
| » W: J.R. Richard (4-0) L: Tom Seaver (1-1) | First | -- |
| Thursday, May 1 |
| » Defeated Reds (13-7), 9-3 | Riverfront Stadium (3-0) | 14-5 | Won 6 |
| » W: Joe Niekro (3-1) L: Mike LaCoss (3-2) | First | -- |
| Friday, May 2 |
| » Lost to Cardinals (9-10), 9-1 | Busch Stadium II (0-1) | 14-6 | |
| » W: Don Hood (1-1) L: Nolan Ryan (1-1) S: Jim Kaat (1) | First | -- |
| Saturday, May 3 |
| » Defeated Cardinals (9-11), 4-2 | Busch Stadium II (1-1) | 15-6 | |
| » W: Vern Ruhle (1-1) L: Silvio Martinez (1-2) S: Joe Sambito (2) | First | -- |
| Sunday, May 4 |
| » Defeated Cardinals (9-12), 4-2 | Busch Stadium II (2-1) | 16-6 | Won 2 |
| » W: Ken Forsch (4-0) L: Bob Sykes (1-3) S: Frank LaCorte (3) | First | -- |
| Monday, May 5 |
| » Lost to Expos (9-13), 10-1 | Stade Olympique (0-1) | 16-7 | |
| » W: David Palmer (1-0) L: J.R. Richard (4-1) | First | -- |
| Tuesday, May 6 |
| » Defeated Expos (9-14), 8-4 | Stade Olympique (1-1) | 17-7 | |
| » W: Joe Niekro (4-1) L: Ross Grimsley (1-2) | First | -- |
| Wednesday, May 7 |
| » Lost to Expos (10-14), 3-0 | Stade Olympique (1-2) | 17-8 | |
| » W: Scott Sanderson (2-2) L: Nolan Ryan (1-2) S: Woodie Fryman (3) | First | -- |
| Friday, May 9 |
| » Lost to Braves (9-15), 5-4 | Atlanta-Fulton County Stadium (0-1) | 17-9 | Lost 2 |
| » W: Larry McWilliams (2-2) L: Ken Forsch (4-1) S: Larry Bradford (1) | First | -- |
| Saturday, May 10 |
| » Defeated Braves (9-16), 3-2 | Atlanta-Fulton County Stadium (1-1) | 18-9 | |
| » W: Frank LaCorte (2-0) L: Gene Garber (1-2) S: Joe Sambito (3) | First | -- |
| Sunday, May 11 |
| » Lost to Braves (10-16), 7-4 | Atlanta-Fulton County Stadium (1-2) | 18-10 | |
| » W: Phil Niekro (2-4) L: Joe Niekro (4-2) | First | -- |
| Tuesday, May 13 |
| » Lost to Expos (12-15), 3-2 | Astrodome (9-4) | 18-11 | Lost 2 |
| » W: David Palmer (2-0) L: Nolan Ryan (1-3) S: Woodie Fryman (4) | Second | 1 out |
| Wednesday, May 14 |
| » Lost to Expos (13-15), 1-0 | Astrodome (9-5) | 18-12 | Lost 3 |
| » W: Scott Sanderson (3-2) L: Ken Forsch (4-2) S: Woodie Fryman (5) | Second | 1 out |
| Friday, May 16 |
| » Lost to Phillies (14-13), 3-0 | Astrodome (9-6) | 18-13 | Lost 4 |
| » W: Dick Ruthven (4-2) L: J.R. Richard (4-2) | Third | 1 out |
| Saturday, May 17 |
| » Lost to Phillies (15-13), 4-2 | Astrodome (9-7) | 18-14 | Lost 5 |
| » W: Larry Christenson (3-0) L: Joe Niekro (4-3) S: Dickie Noles (3) | Third | 1½ out |
| Sunday, May 18 |
| » Defeated Phillies (15-14), 3-0 | Astrodome (10-7) | 19-14 | |
| » W: Nolan Ryan (2-3) L: Randy Lerch (0-6) | Third | 1½ out |
| Tuesday, May 20 |
| » Defeated Mets (12-20), 3-2 | Shea Stadium (1-0) | 20-14 | Won 2 |
| » W: Ken Forsch (5-2) L: Craig Swan (2-3) | Second | 2 out |
| Wednesday, May 21 |
| » Lost to Mets (13-20), 5-1 | Shea Stadium (1-1) | 20-15 | |
| » W: Pete Falcone (3-2) L: J.R. Richard (4-3) S: Neil Allen (7) | Second | 3 out |
| Thursday, May 22 |
| » Defeated Mets (13-21), 8-5 | Shea Stadium (2-1) | 21-15 | |
| » W: Joe Niekro (5-3) L: Kevin Kobel (0-4) S: Frank LaCorte (4) | Second | 2½ out |
| Friday, May 23 |
| » Lost to Phillies (18-15), 3-0 | Veteran's Stadium (0-1) | 21-16 | |
| » W: Steve Carlton (8-2) L: Nolan Ryan (2-4) | Second | 2½ out |
| Saturday, May 24 |
| » Lost to Phillies (19-15), 5-4 | Veteran's Stadium (0-2) | 21-17 | Lost 2 |
| » W: Kevin Saucier (2-0) L: Joaquin Andujar (0-2) S: Tug McGraw (3) | Third | 3½ out |
| Sunday, May 25 |
| » Lost to Phillies (20-15), 6-2 | Veteran's Stadium (0-3) | 21-18 | Lost 3 |
| » W: Dick Ruthven (5-3) L: Ken Forsch (5-3) | Third | 3½ out |
| Monday, May 26 |
| » Defeated Padres (22-20), 4-1 | Astrodome (11-7) | 22-18 | |
| » W: J.R. Richard (5-3) L: John Curtis (3-4) S: Joe Sambito (4) | Second | 3 out |
| Tuesday, May 27 |
| » Defeated Padres (22-21), 4-3 | Astrodome (12-7) | 23-18 | Won 2 |
| » W: Frank LaCorte (3-0) L: Rollie Fingers (5-5) | Second | 2 out |
| Wednesday, May 28 |
| » Defeated Padres (22-22), 1-0 | Astrodome (13-7) | 24-18 | Won 3 |
| » W: Nolan Ryan (3-4) L: Rick Wise (2-3) | Second | 1½ out |
| Friday, May 30 |
| » Lost to Giants (19-26), 3-2 | Candlestick Park (0-1) | 24-19 | |
| » W: Vida Blue (8-2) L: Ken Forsch (5-4) | Third | 3 out |
| Saturday, May 31 |
| » Defeated Giants (19-27), 5-0 | Candlestick Park (1-1) | 25-19 | |
| » W: J.R. Richard (6-3) L: John Montefusco (2-4) | Second | 2 out |
| Sunday, June 1 |
| » Lost to Giants (20-27), 6-2 | Candlestick Park (1-2) | 25-20 | |
| » W: Bob Knepper (4-6) L: Joe Niekro (5-4) | Third | 2 out |
| Monday, June 2 |
| » Lost to Padres (24-25), 3-0 | San Diego/Jack Murphy Stadium (0-1) | 25-21 | Lost 2 |
| » W: Rick Wise (3-3) L: Nolan Ryan (3-5) S: Eric Rasmussen (1) | Third | 3 out |
| Tuesday, June 3 |
| » Defeated Padres (24-26), 3-2 | San Diego/Jack Murphy Stadium (1-1) | 26-21 | |
| » W: Vern Ruhle (2-1) L: Randy Jones (4-4) S: Frank LaCorte (5) | Second | 3 out |
| Wednesday, June 4 |
| » Defeated Padres (24-27), 4-3 | San Diego/Jack Murphy Stadium (2-1) | 27-21 | Won 2 |
| » W: Ken Forsch (6-4) L: Rollie Fingers (5-6) S: Joe Sambito (5) | Second | 2 out |
| Friday, June 6 |
| » Defeated Giants (21-30), 2-0 | Astrodome (14-7) | 28-21 | Won 3 |
| » W: J.R. Richard (7-3) L: Bob Knepper (4-7) | Second | 2 out |
| Saturday, June 7 |
| » Defeated Giants (21-31), 3-0 | Astrodome (15-7) | 29-21 | Won 4 |
| » W: Joe Niekro (6-4) L: Ed Whitson (2-7) | Second | 1 out |
| » Major-league debuts: Rich Murray (Giants) |
| Sunday, June 8 |
| » Defeated Giants (21-32), 5-4 | Astrodome (16-7) | 30-21 | Won 5 |
| » W: Joe Sambito (2-0) L: Greg Minton (2-3) | Second | 1 out |
| Monday, June 9 |
| » Defeated Cubs (22-27), 6-2 | Astrodome (17-7) | 31-21 | Won 6 |
| » W: Ken Forsch (7-4) L: Dennis Lamp (4-6) | Second | ½ out |
| Tuesday, June 10 |
| » Defeated Cubs (22-28), 5-2 | Astrodome (18-7) | 32-21 | Won 7 |
| » W: Vern Ruhle (3-1) L: Mike Krukow (3-7) | First | -- |
| Wednesday, June 11 |
| » Defeated Cubs (22-29), 3-0 | Astrodome (19-7) | 33-21 | Won 8 |
| » W: J.R. Richard (8-3) L: Rick Reuschel (5-6) | First | -- |
| Friday, June 13 |
| » Lost to Pirates (32-23), 5-3 | Three Rivers Stadium (0-1) | 33-22 | |
| » W: Eddie Solomon (4-0) L: Joe Niekro (6-5) S: Kent Tekulve (9) | First | -- |
| Saturday, June 14 |
| » Defeated Pirates (32-24), 7-3 | Three Rivers Stadium (1-1) | 34-22 | |
| » W: Nolan Ryan (4-5) L: Don Robinson (2-2) S: Frank LaCorte (6) | First | -- |
| Sunday, June 15 |
| » Lost to Pirates (33-24), 4-1 | Three Rivers Stadium (1-2) | 34-23 | |
| » W: John Candelaria (4-5) L: Ken Forsch (7-5) | First | -- |
| Monday, June 16 |
| » Defeated Cubs (24-31), 2-1 | Wrigley Field (1-0) | 35-23 | |
| » W: Vern Ruhle (4-1) L: Willie Hernandez (1-5) S: Dave Smith (1) | First | -- |
| Tuesday, June 17 |
| » Defeated Cubs (24-32), 7-1 | Wrigley Field (2-0) | 36-23 | Won 2 |
| » W: J.R. Richard (9-3) L: Lynn McGlothen (3-4) S: Joaquin Andujar (2) | First | -- |
| Wednesday, June 18 |
| » Defeated Cardinals (23-38), 3-0 | Astrodome (20-7) | 37-23 | Won 3 |
| » W: Joe Niekro (7-5) L: Jim Kaat (1-5) | First | -- |
| Thursday, June 19 |
| » Defeated Cardinals (23-39), 2-0 | Astrodome (21-7) | 38-23 | Won 4 |
| » W: Nolan Ryan (5-5) L: Bob Sykes (1-6) S: Joe Sambito (6) | First | -- |
| Friday, June 20 |
| » Defeated Pirates (34-29), 6-4 | Astrodome (22-7) | 39-23 | Won 5 |
| » W: Ken Forsch (8-5) L: John Candelaria (4-6) S: Joe Sambito (7) | First | -- |
| Saturday, June 21 |
| » Defeated Pirates (34-30), 4-2 | Astrodome (23-7) | 40-23 | Won 6 |
| » W: Vern Ruhle (5-1) L: Bert Blyleven (2-7) S: Joe Sambito (8) | First | -- |
| Sunday, June 22 |
| » Lost to Pirates (35-30), 2-1 | Astrodome (23-8) | 40-24 | |
| » W: Jim Bibby (8-1) L: Joe Niekro (7-6) S: Grant Jackson (3) | First | -- |
| Monday, June 23 |
| » Lost to Dodgers (39-28), 3-0 | Astrodome (23-9) | 40-25 | Lost 2 |
| » W: Rick Sutcliffe (2-4) L: Joaquin Andujar (0-3) | First | -- |
| Tuesday, June 24 |
| » Defeated Dodgers (39-29), 5-4 | Astrodome (24-9) | 41-25 | |
| » W: Frank LaCorte (4-0) L: Joe Beckwith (3-1) | First | -- |
| Wednesday, June 25 |
| » Lost to Dodgers (40-29), 9-2 | Astrodome (24-10) | 41-26 | |
| » W: Bob Welch (8-2) L: Ken Forsch (8-6) | First | -- |
| Friday, June 27 |
| » Defeated Reds (36-33), 5-4 | Astrodome (25-10) | 42-26 | |
| » W: Joe Niekro (8-6) L: Frank Pastore (9-4) S: Joe Sambito (9) | First | -- |
| Saturday, June 28 |
| » Lost to Reds (37-33), 8-5 | Astrodome (25-11) | 42-27 | |
| » W: Joe Price (1-0) L: J.R. Richard (9-4) S: Tom Hume (11) | First | -- |
| Sunday, June 29 |
| » Defeated Reds (37-34), 12-10 | Astrodome (26-11) | 43-27 | |
| » W: Frank LaCorte (5-0) L: Mario Soto (0-3) S: Joe Sambito (10) | First | -- |
| Monday, June 30 |
| » Lost to Braves (32-39), 5-4 | Atlanta-Fulton County Stadium (1-3) | 43-28 | |
| » W: Al Hrabosky (4-1) L: Joe Sambito (2-1) | First | -- |
| Tuesday, July 1 |
| » Lost to Braves (33-39), 13-4 | Atlanta-Fulton County Stadium (1-4) | 43-29 | Lost 2 |
| » W: Doyle Alexander (6-3) L: Joe Niekro (8-7) | First | -- |
| Wednesday, July 2 |
| » Lost to Braves (34-39), 14-0 | Atlanta-Fulton County Stadium (1-5) | 43-30 | Lost 3 |
| » W: Phil Niekro (6-10) L: Vern Ruhle (5-2) | First | -- |
| Thursday, July 3 |
| » Defeated Braves (34-40), 5-3 | Atlanta-Fulton County Stadium (2-5) | 44-30 | |
| » W: J.R. Richard (10-4) L: Tommy Boggs (3-4) S: Frank LaCorte (7) | First | -- |
| Friday, July 4 |
| » Lost to Reds (39-37), 8-1 | Riverfront Stadium (3-1) | 44-31 | |
| » W: Charlie Leibrandt (8-4) L: Nolan Ryan (5-6) | First | -- |
| Saturday, July 5 |
| » Lost to Reds (40-37), 8-6 | Riverfront Stadium (3-2) | 44-32 | Lost 2 |
| » W: Mario Soto (1-3) L: Ken Forsch (8-7) | Second | 1 out |
| » Lost to Reds (41-37), 3-2 | Riverfront Stadium (3-3) | 44-33 | Lost 3 |
| » W: Mike LaCoss (5-7) L: Joaquin Andujar (0-4) S: Tom Hume (12) | Second | 1 out |
| » Major-league debuts: Bruce Berenyi (Reds) |
| Sunday, July 6 |
| » Defeated Reds (41-38), 3-2 | Riverfront Stadium (4-3) | 45-33 | |
| » W: Joe Niekro (9-7) L: Frank Pastore (10-5) S: Frank LaCorte (8) | First | -- |
| Thursday, July 10 |
| » Lost to Dodgers (47-34), 4-3 | Dodger Stadium (2-3) | 45-34 | |
| » W: Steve Howe (3-4) L: Nolan Ryan (5-7) | Second | 1 out |
| Friday, July 11 |
| » Lost to Dodgers (48-34), 3-2 | Dodger Stadium (2-4) | 45-35 | Lost 2 |
| » W: Jerry Reuss (10-2) L: Ken Forsch (8-8) S: Steve Howe (8) | Second | 2 out |
| Saturday, July 12 |
| » Defeated Braves (37-43), 9-5 | Astrodome (27-11) | 46-35 | |
| » W: Joe Niekro (10-7) L: Larry McWilliams (5-6) S: Dave Smith (2) | Second | 1 out |
| Sunday, July 13 |
| » Defeated Braves (37-44), 6-5 | Astrodome (28-11) | 47-35 | Won 2 |
| » W: Joe Sambito (3-1) L: Gene Garber (2-5) S: Frank LaCorte (9) | First | -- |
| » Defeated Braves (37-45), 6-1 | Astrodome (29-11) | 48-35 | Won 3 |
| » W: Vern Ruhle (6-2) L: Tommy Boggs (3-5) | First | -- |
| Monday, July 14 |
| » Lost to Braves (38-45), 2-0 | Astrodome (29-12) | 48-36 | |
| » W: Phil Niekro (7-11) L: Gordie Pladson (0-1) | First | -- |
| Tuesday, July 15 |
| » Defeated Phillies (44-38), 3-2 | Astrodome (30-12) | 49-36 | |
| » W: Joe Sambito (4-1) L: Dick Ruthven (8-6) | First | -- |
| Wednesday, July 16 |
| » Lost to Phillies (45-38), 4-2 | Astrodome (30-13) | 49-37 | |
| » W: Bob Walk (6-0) L: Ken Forsch (8-9) | First | -- |
| Thursday, July 17 |
| » Lost to Phillies (46-38), 2-1 | Astrodome (30-14) | 49-38 | Lost 2 |
| » W: Steve Carlton (15-4) L: Joe Niekro (10-8) | Second | ½ out |
| Friday, July 18 |
| » Lost to Expos (48-37), 5-4 | Astrodome (30-15) | 49-39 | Lost 3 |
| » W: Woodie Fryman (4-4) L: Dave Smith (1-3) S: Fred Norman (4) | Second | ½ out |
| Saturday, July 19 |
| » Defeated Expos (48-38), 4-2 | Astrodome (31-15) | 50-39 | |
| » W: Joaquin Andujar (1-4) L: Charlie Lea (2-4) S: Dave Smith (3) | First | -- |
| » Lost to Expos (49-38), 5-2 | Astrodome (31-16) | 50-40 | |
| » W: Bill Gullickson (1-2) L: Gordie Pladson (0-2) | First | -- |
| Sunday, July 20 |
| » Defeated Expos (49-39), 4-3 | Astrodome (32-16) | 51-40 | |
| » W: Joe Sambito (5-1) L: Fred Norman (0-1) | First | -- |
| Monday, July 21 |
| » Defeated Mets (44-47), 3-2 | Astrodome (33-16) | 52-40 | Won 2 |
| » W: Frank LaCorte (6-0) L: Neil Allen (4-6) | First | -- |
| Tuesday, July 22 |
| » Defeated Mets (44-48), 6-5 | Astrodome (34-16) | 53-40 | Won 3 |
| » W: Bert Roberge (1-0) L: Ed Glynn (3-3) S: Dave Smith (4) | First | -- |
| Wednesday, July 23 |
| » Lost to Mets (45-48), 4-3 | Astrodome (34-17) | 53-41 | |
| » W: Jeff Reardon (5-5) L: Frank LaCorte (6-1) S: Neil Allen (16) | First | -- |
| Friday, July 25 |
| » Defeated Expos (50-42), 9-8 | Stade Olympique (2-2) | 54-41 | |
| » W: Frank LaCorte (7-1) L: Elias Sosa (5-4) | First | -- |
| Saturday, July 26 |
| » Lost to Expos (51-42), 2-1 | Stade Olympique (2-3) | 54-42 | |
| » W: Stan Bahnsen (7-4) L: Frank LaCorte (7-2) | First | -- |
| Sunday, July 27 |
| » Defeated Expos (51-43), 6-3 | Stade Olympique (3-3) | 55-42 | |
| » W: Joe Niekro (11-8) L: Bill Lee (3-5) S: Dave Smith (5) | First | -- |
| Monday, July 28 |
| » Defeated Phillies (50-46), 3-2 | Veteran's Stadium (1-3) | 56-42 | Won 2 |
| » W: Joe Sambito (6-1) L: Ron Reed (6-4) | First | -- |
| Tuesday, July 29 |
| » Lost to Phillies (51-46), 9-6 | Veteran's Stadium (1-4) | 56-43 | |
| » W: Kevin Saucier (5-3) L: Frank LaCorte (7-3) S: Tug McGraw (8) | First | -- |
| Wednesday, July 30 |
| » Lost to Phillies (52-46), 6-4 | Veteran's Stadium (1-5) | 56-44 | Lost 2 |
| » W: Dick Ruthven (10-7) L: Nolan Ryan (5-8) S: Tug McGraw (9) | First | -- |
| Friday, August 1 |
| » Lost to Mets (49-51), 5-4 | Shea Stadium (2-2) | 56-45 | Lost 3 |
| » W: Jeff Reardon (6-5) L: Dave Smith (1-4) | First | -- |
| Saturday, August 2 |
| » Lost to Mets (50-51), 5-3 | Shea Stadium (2-3) | 56-46 | Lost 4 |
| » W: Neil Allen (5-6) L: Joe Niekro (11-9) | Second | ½ out |
| Sunday, August 3 |
| » Defeated Mets (50-52), 3-2 | Shea Stadium (3-3) | 57-46 | |
| » W: Joe Sambito (7-1) L: Jeff Reardon (6-6) | First | -- |
| Monday, August 4 |
| » Defeated Giants (51-55), 4-2 | Astrodome (35-17) | 58-46 | Won 2 |
| » W: Nolan Ryan (6-8) L: Alan Hargesheimer (2-1) S: Joe Sambito (11) | First | -- |
| Tuesday, August 5 |
| » Lost to Giants (52-55), 9-3 | Astrodome (35-18) | 58-47 | |
| » W: Gary Lavelle (5-5) L: Gordie Pladson (0-3) | First | -- |
| Wednesday, August 6 |
| » Defeated Giants (52-56), 1-0 | Astrodome (36-18) | 59-47 | |
| » W: Ken Forsch (9-9) L: Vida Blue (9-6) | First | -- |
| Thursday, August 7 |
| » Lost to Padres (48-61), 5-1 | Astrodome (36-19) | 59-48 | |
| » W: Bob Shirley (9-7) L: Joe Niekro (11-10) | First | -- |
| Friday, August 8 |
| » Lost to Padres (49-61), 5-3 | Astrodome (36-20) | 59-49 | Lost 2 |
| » W: Juan Eichelberger (3-0) L: Joe Sambito (7-2) S: Rollie Fingers (15) | First | -- |
| Saturday, August 9 |
| » Defeated Padres (49-62), 9-5 | Astrodome (37-20) | 60-49 | |
| » W: Dave Smith (2-4) L: John D'Acquisto (2-3) | First | -- |
| Sunday, August 10 |
| » Lost to Padres (50-62), 3-2 | Astrodome (37-21) | 60-50 | |
| » W: Rick Wise (4-5) L: Joe Sambito (7-3) | Second | ½ out |
| Monday, August 11 |
| » Lost to Giants (54-58), 5-4 | Candlestick Park (1-3) | 60-51 | Lost 2 |
| » W: Vida Blue (10-6) L: Ken Forsch (9-10) S: Greg Minton (12) | Second | ½ out |
| Tuesday, August 12 |
| » Lost to Giants (55-58), 2-0 | Candlestick Park (1-4) | 60-52 | Lost 3 |
| » W: Allen Ripley (6-5) L: Joe Niekro (11-11) S: Gary Lavelle (7) | Second | ½ out |
| Wednesday, August 13 |
| » Lost to Giants (56-58), 6-5 | Candlestick Park (1-5) | 60-53 | Lost 4 |
| » W: Mike Rowland (1-0) L: Dave Smith (2-5) | Third | 1 out |
| Thursday, August 14 |
| » Defeated Padres (50-66), 2-1 | San Diego/Jack Murphy Stadium (3-1) | 61-53 | |
| » W: Nolan Ryan (7-8) L: John Curtis (4-8) | Second | ½ out |
| Friday, August 15 |
| » Defeated Padres (50-67), 3-1 | San Diego/Jack Murphy Stadium (4-1) | 62-53 | Won 2 |
| » W: Dave Smith (3-5) L: Eric Rasmussen (2-9) | First | -- |
| » Major-league debuts: Luis Salazar (Padres) |
| Sunday, August 17 |
| » Defeated Padres (50-68), 5-0 | San Diego/Jack Murphy Stadium (5-1) | 63-53 | Won 3 |
| » W: Ken Forsch (10-10) L: Randy Jones (5-12) | First | -- |
| » Defeated Padres (50-69), 9-2 | San Diego/Jack Murphy Stadium (6-1) | 64-53 | Won 4 |
| » W: Joe Niekro (12-11) L: Steve Mura (4-5) | First | -- |
| Tuesday, August 19 |
| » Defeated Pirates (67-52), 5-2 | Astrodome (38-21) | 65-53 | Won 5 |
| » W: Nolan Ryan (8-8) L: John Candelaria (8-13) S: Joe Sambito (12) | First | -- |
| Wednesday, August 20 |
| » Defeated Pirates (67-53), 5-1 | Astrodome (39-21) | 66-53 | Won 6 |
| » W: Vern Ruhle (7-2) L: Jim Bibby (15-3) S: Dave Smith (6) | First | -- |
| Thursday, August 21 |
| » Defeated Pirates (67-54), 12-5 | Astrodome (40-21) | 67-53 | Won 7 |
| » W: Joe Sambito (8-3) L: Bert Blyleven (7-9) | First | -- |
| Friday, August 22 |
| » Defeated Cubs (49-71), 3-2 | Astrodome (41-21) | 68-53 | Won 8 |
| » W: Frank LaCorte (8-3) L: Bill Caudill (1-4) | First | -- |
| Saturday, August 23 |
| » Defeated Cubs (49-72), 1-0 | Astrodome (42-21) | 69-53 | Won 9 |
| » W: Joe Niekro (13-11) L: George Riley (0-4) | First | -- |
| Sunday, August 24 |
| » Defeated Cubs (49-73), 2-1 | Astrodome (43-21) | 70-53 | Won 10 |
| » W: Nolan Ryan (9-8) L: Bill Caudill (1-5) | First | -- |
| Monday, August 25 |
| » Lost to Cardinals (54-68), 3-1 | Busch Stadium II (2-2) | 70-54 | |
| » W: Don Hood (3-5) L: Vern Ruhle (7-3) | First | -- |
| Tuesday, August 26 |
| » Defeated Cardinals (54-69), 7-2 | Busch Stadium II (3-2) | 71-54 | |
| » W: Joe Niekro (14-11) L: Jim Kaat (5-7) | First | -- |
| Wednesday, August 27 |
| » Lost to Cardinals (55-69), 10-2 | Busch Stadium II (3-3) | 71-55 | |
| » W: John Martin (1-0) L: Ken Forsch (10-11) | First | -- |
| » Major-league debuts: John Martin (Cardinals) |
| Thursday, August 28 |
| » Defeated Cubs (50-75), 4-1 | Wrigley Field (3-0) | 72-55 | |
| » W: Joaquin Andujar (2-4) L: Dennis Lamp (10-10) S: Joe Sambito (13) | First | -- |
| Friday, August 29 |
| » Defeated Cubs (50-76), 6-5 | Wrigley Field (4-0) | 73-55 | Won 2 |
| » W: Dave Smith (4-5) L: Dick Tidrow (5-5) S: Frank LaCorte (10) | First | -- |
| Saturday, August 30 |
| » Defeated Cubs (50-77), 2-0 | Wrigley Field (5-0) | 74-55 | Won 3 |
| » W: Vern Ruhle (8-3) L: Lynn McGlothen (9-10) | First | -- |
| Sunday, August 31 |
| » Lost to Cubs (51-77), 8-7 | Wrigley Field (5-1) | 74-56 | |
| » W: Dick Tidrow (6-5) L: Frank LaCorte (8-4) | First | -- |
| Monday, September 1 |
| » Defeated Pirates (70-62), 10-4 | Three Rivers Stadium (2-2) | 75-56 | |
| » W: Dave Smith (5-5) L: Don Robinson (5-8) | First | -- |
| » Lost to Pirates (71-62), 7-5 | Three Rivers Stadium (2-3) | 75-57 | |
| » W: Rick Rhoden (5-4) L: Gordie Pladson (0-4) S: Grant Jackson (8) | First | -- |
| » Major-league debuts: Tony Pena (Pirates) |
| Wednesday, September 3 |
| » Lost to Pirates (72-62), 10-4 | Three Rivers Stadium (2-4) | 75-58 | Lost 2 |
| » W: John Candelaria (10-13) L: Joaquin Andujar (2-5) S: Enrique Romo (9) | Second | 1 out |
| Friday, September 5 |
| » Lost to Cardinals (60-72), 7-5 | Astrodome (43-22) | 75-59 | Lost 3 |
| » W: Kim Seaman (3-1) L: Joe Sambito (8-4) S: George Frazier (2) | Second | 1½ out |
| Saturday, September 6 |
| » Defeated Cardinals (60-73), 9-5 | Astrodome (44-22) | 76-59 | |
| » W: Joe Niekro (15-11) L: Bob Sykes (6-10) S: Randy Niemann (1) | Second | 1 out |
| » Defeated Cardinals (60-74), 6-4 | Astrodome (45-22) | 77-59 | Won 2 |
| » W: Vern Ruhle (9-3) L: John Martin (1-1) | Second | 1 out |
| Sunday, September 7 |
| » Lost to Cardinals (61-74), 2-0 | Astrodome (45-23) | 77-60 | |
| » W: Pete Vuckovich (10-9) L: Ken Forsch (10-12) | Second | 2 out |
| Tuesday, September 9 |
| » Defeated Dodgers (79-59), 5-4 | Astrodome (46-23) | 78-60 | |
| » W: Dave Smith (6-5) L: Steve Howe (6-7) S: Joe Sambito (14) | Second | 1 out |
| Wednesday, September 10 |
| » Defeated Dodgers (79-60), 6-5 | Astrodome (47-23) | 79-60 | Won 2 |
| » W: Bert Roberge (2-0) L: Rick Sutcliffe (3-9) | First | -- |
| Friday, September 12 |
| » Defeated Giants (67-73), 5-3 | Astrodome (48-23) | 80-60 | Won 3 |
| » W: Joe Niekro (16-11) L: Ed Whitson (9-11) S: Dave Smith (7) | First | -- |
| Saturday, September 13 |
| » Defeated Giants (67-74), 3-2 | Astrodome (49-23) | 81-60 | Won 4 |
| » W: Ken Forsch (11-12) L: Vida Blue (13-8) | First | -- |
| Sunday, September 14 |
| » Defeated Giants (67-75), 6-4 | Astrodome (50-23) | 82-60 | Won 5 |
| » W: Joaquin Andujar (3-5) L: John Montefusco (4-8) S: Joe Sambito (15) | First | -- |
| Monday, September 15 |
| » Lost to Padres (63-81), 6-3 | Astrodome (50-24) | 82-61 | |
| » W: Bob Shirley (11-10) L: Nolan Ryan (9-9) | First | -- |
| Tuesday, September 16 |
| » Lost to Padres (64-81), 4-3 | Astrodome (50-25) | 82-62 | Lost 2 |
| » W: John Curtis (8-8) L: Vern Ruhle (9-4) S: Rollie Fingers (21) | First | -- |
| Wednesday, September 17 |
| » Lost to Reds (79-67), 7-0 | Riverfront Stadium (4-4) | 82-63 | Lost 3 |
| » W: Mario Soto (10-6) L: Joe Niekro (16-12) | Second | 1 out |
| Thursday, September 18 |
| » Defeated Reds (79-68), 10-2 | Riverfront Stadium (5-4) | 83-63 | |
| » W: Ken Forsch (12-12) L: Frank Pastore (11-7) S: Joe Sambito (16) | Second | 1 out |
| Friday, September 19 |
| » Lost to Giants (70-77), 4-3 | Candlestick Park (1-6) | 83-64 | |
| » W: Tom Griffin (4-1) L: Joaquin Andujar (3-6) S: Al Holland (6) | Second | 1 out |
| Saturday, September 20 |
| » Defeated Giants (70-78), 3-2 | Candlestick Park (2-6) | 84-64 | |
| » W: Dave Smith (7-5) L: Gary Lavelle (6-7) S: Joe Sambito (17) | First | -- |
| Sunday, September 21 |
| » Defeated Giants (70-79), 5-1 | Candlestick Park (3-6) | 85-64 | Won 2 |
| » W: Vern Ruhle (10-4) L: Vida Blue (14-9) | First | -- |
| Monday, September 22 |
| » Defeated Padres (67-84), 4-2 | San Diego/Jack Murphy Stadium (7-1) | 86-64 | Won 3 |
| » W: Joe Niekro (17-12) L: Bob Shirley (11-11) | First | -- |
| Tuesday, September 23 |
| » Lost to Padres (68-84), 9-4 | San Diego/Jack Murphy Stadium (7-2) | 86-65 | |
| » W: John Curtis (9-8) L: Randy Niemann (0-1) | First | -- |
| Wednesday, September 24 |
| » Lost to Braves (79-73), 4-2 | Atlanta-Fulton County Stadium (2-6) | 86-66 | Lost 2 |
| » W: Doyle Alexander (14-9) L: Joaquin Andujar (3-7) S: Rick Camp (20) | First | -- |
| Thursday, September 25 |
| » Defeated Braves (79-74), 4-2 | Atlanta-Fulton County Stadium (3-6) | 87-66 | |
| » W: Nolan Ryan (10-9) L: Phil Niekro (15-16) S: Dave Smith (8) | First | -- |
| Friday, September 26 |
| » Defeated Reds (85-70), 2-0 | Astrodome (51-25) | 88-66 | Won 2 |
| » W: Vern Ruhle (11-4) L: Tom Seaver (10-8) | First | -- |
| Saturday, September 27 |
| » Defeated Reds (85-71), 2-0 | Astrodome (52-25) | 89-66 | Won 3 |
| » W: Joe Niekro (18-12) L: Mario Soto (10-7) S: Dave Smith (9) | First | -- |
| Sunday, September 28 |
| » Lost to Reds (86-71), 8-5 | Astrodome (52-26) | 89-67 | |
| » W: Mike LaCoss (10-12) L: Joaquin Andujar (3-8) S: Tom Hume (24) | First | -- |
| Tuesday, September 30 |
| » Defeated Braves (80-76), 7-3 | Astrodome (53-26) | 90-67</ |
