| Thursday, January 12 |
| Future Astro Mike Simms is born in Orange, CA. |
| Thursday, April 6 |
| Future Astro Tommy Greene is born in Lumberton, NC. |
| Tuesday, April 11 |
| » Defeated Braves (0-1), 6-1 | Astrodome (1-0) | 1-0 | |
| » Starters: Denny Lemaster vs Mike Cuellar | First | -- |
| » Major-league debuts: Ramon Hernandez (Braves) |
| Wednesday, April 12 |
| » Defeated Braves (0-2), 4-2 | Astrodome (2-0) | 2-0 | Won 2 |
| » Starters: Ken Johnson vs Larry Dierker | First | -- |
| Thursday, April 13 |
| » Lost to Reds (2-0), 5-4 | Crosley Field (0-1) | 2-1 | |
| » Starters: Dave Giusti vs Milt Pappas | Third | ½ out |
| Friday, April 14 |
| » Defeated Reds (2-1), 8-2 | Crosley Field (1-1) | 3-1 | |
| » Starters: Don Wilson vs Sammy Ellis | Second | 1 out |
| Saturday, April 15 |
| » Lost to Reds (3-1), 7-3 | Crosley Field (1-2) | 3-2 | |
| » Starters: Chris Zachary vs Gary Nolan | Third | 1 out |
| » Major-league debuts: Gary Nolan (Reds) |
| Sunday, April 16 |
| » Lost to Cardinals (4-0), 11-8 | Busch Stadium II (0-1) | 3-3 | Lost 2 |
| » Starters: Mike Cuellar vs Bob Gibson | Fifth | 2 out |
| Tuesday, April 18 |
| » Lost to Braves (4-3), 3-2 | Atlanta-Fulton County Stadium (0-1) | 3-4 | Lost 3 |
| » Starters: Larry Dierker vs Tony Cloninger | Fifth | 3 out |
| Wednesday, April 19 |
| » Lost to Braves (5-3), 4-1 | Atlanta-Fulton County Stadium (0-2) | 3-5 | Lost 4 |
| » Starters: Dave Giusti vs Ken Johnson | Fourth | 4 out |
| Thursday, April 20 |
| » Major-league debuts: Clarence Jones (Cubs) |
| Friday, April 21 |
| » Lost to Reds (7-3), 3-1 | Astrodome (2-1) | 3-6 | Lost 5 |
| » Starters: Billy McCool vs Mike Cuellar | Seventh | 4 out |
| Saturday, April 22 |
| » Lost to Reds (8-3), 7-2 | Astrodome (2-2) | 3-7 | Lost 6 |
| » Starters: Jim Maloney vs Larry Dierker | Eighth | 5 out |
| Sunday, April 23 |
| » Lost to Reds (9-3), 5-3 | Astrodome (2-3) | 3-8 | Lost 7 |
| » Starters: Milt Pappas vs Don Wilson | Ninth | 5 out |
| Monday, April 24 |
| » Lost to Reds (10-3), 3-1 | Astrodome (2-4) | 3-9 | Lost 8 |
| » Starters: Sammy Ellis vs Dave Giusti | Eighth | 6½ out |
| Tuesday, April 25 |
| » Lost to Cardinals (8-3), 4-0 | Astrodome (2-5) | 3-10 | Lost 9 |
| » Starters: Al Jackson vs Chris Zachary | Ninth | 6 out |
| Wednesday, April 26 |
| » Lost to Cardinals (9-3), 7-2 | Astrodome (2-6) | 3-11 | Lost 10 |
| » Starters: Steve Carlton vs Mike Cuellar | Ninth | 7 out |
| Thursday, April 27 |
| » Defeated Cardinals (9-4), 6-4 | Astrodome (3-6) | 4-11 | |
| » Starters: Bob Gibson vs Larry Dierker | Tenth | 7½ out |
| Future Astro Tony Eusebio is born in San Jose de los Llanos, D.R. |
| Friday, April 28 |
| » Defeated Cubs (6-6), 5-4 | Astrodome (4-6) | 5-11 | Won 2 |
| » Starters: Curt Simmons vs Don Wilson | Eighth | 7½ out |
| Saturday, April 29 |
| » Lost to Cubs (7-6), 4-1 | Astrodome (4-7) | 5-12 | |
| » Starters: Ken Holtzman vs Dave Giusti | Ninth | 8½ out |
| Sunday, April 30 |
| » Lost to Cubs (8-6), 4-1 | Astrodome (4-8) | 5-13 | Lost 2 |
| » Starters: Rich Nye vs Bo Belinsky | Tenth | 9 out |
| Tuesday, May 2 |
| » Defeated Phillies (8-9), 10-3 | Shibe Park (1-0) | 6-13 | |
| » Starters: Mike Cuellar vs Larry Jackson | Eighth | 8 out |
| Wednesday, May 3 |
| » Lost to Phillies (9-9), 1-0 | Shibe Park (1-1) | 6-14 | |
| » Starters: Larry Dierker vs Chris Short | Ninth | 8 out |
| Thursday, May 4 |
| » Defeated Phillies (9-10), 4-1 | Shibe Park (2-1) | 7-14 | |
| » Starters: Don Wilson vs Dick Ellsworth | Eighth | 7½ out |
| Friday, May 5 |
| » Lost to Mets (8-13), 3-2 | Shea Stadium (0-1) | 7-15 | |
| » Starters: Dave Giusti vs Tom Seaver | Ninth | 8½ out |
| Monday, May 8 |
| » Lost to Dodgers (8-13), 4-2 | Astrodome (4-9) | 7-16 | Lost 2 |
| » Starters: Claude Osteen vs Mike Cuellar | Eighth | 9 out |
| Tuesday, May 9 |
| » Defeated Dodgers (8-14), 5-2 | Astrodome (5-9) | 8-16 | |
| » Starters: Don Sutton vs Larry Dierker | Ninth | 8 out |
| Wednesday, May 10 |
| » Lost to Dodgers (9-14), 5-1 | Astrodome (5-10) | 8-17 | |
| » Starters: Don Drysdale vs Dave Giusti | Ninth | 9 out |
| Friday, May 12 |
| » Lost to Giants (11-14), 6-1 | Candlestick Park (0-1) | 8-18 | Lost 2 |
| » Starters: Chris Zachary vs Juan Marichal | Ninth | 10 out |
| Saturday, May 13 |
| » Lost to Giants (12-14), 4-3 | Candlestick Park (0-2) | 8-19 | Lost 3 |
| » Starters: Mike Cuellar vs Mike McCormick | Tenth | 10 out |
| Sunday, May 14 |
| » Lost to Giants (13-14), 11-6 | Candlestick Park (0-3) | 8-20 | Lost 4 |
| » Starters: Larry Dierker vs Gaylord Perry | Eighth | 12 out |
| » Lost to Giants (14-14), 4-3 | Candlestick Park (0-4) | 8-21 | Lost 5 |
| » Starters: Don Wilson vs Bobby Bolin | Eighth | 12 out |
| Monday, May 15 |
| » Defeated Dodgers (10-18), 5-3 | Dodger Stadium (1-0) | 9-21 | |
| » Starters: Dave Giusti vs Jim Brewer | Tenth | 12 out |
| Tuesday, May 16 |
| » Lost to Dodgers (11-18), 6-1 | Dodger Stadium (1-1) | 9-22 | |
| » Starters: Chris Zachary vs Claude Osteen | Ninth | 13 out |
| Future Astro Doug Brocail is born in Clearfield, PA. |
| Wednesday, May 17 |
| » Lost to Dodgers (12-18), 7-0 | Dodger Stadium (1-2) | 9-23 | Lost 2 |
| » Starters: Mike Cuellar vs Don Sutton | Tenth | 14 out |
| Thursday, May 18 |
| » Defeated Giants (16-16), 6-2 | Astrodome (6-10) | 10-23 | |
| » Starters: Gaylord Perry vs Larry Dierker | Tenth | 13 out |
| Friday, May 19 |
| » Lost to Giants (17-16), 6-2 | Astrodome (6-11) | 10-24 | |
| » Starters: Ray Sadecki vs Don Wilson | Tenth | 14 out |
| Saturday, May 20 |
| » Lost to Giants (18-16), 3-2 | Astrodome (6-12) | 10-25 | Lost 2 |
| » Starters: Juan Marichal vs Dave Giusti | Tenth | 15 out |
| Sunday, May 21 |
| » Defeated Giants (18-17), 2-0 | Astrodome (7-12) | 11-25 | |
| » Starters: Mike McCormick vs Mike Cuellar | Tenth | 14 out |
| Monday, May 22 |
| » Lost to Pirates (19-14), 3-1 | Astrodome (7-13) | 11-26 | |
| » Starters: Tommie Sisk vs Chris Zachary | Tenth | 14½ out |
| Tuesday, May 23 |
| » Defeated Pirates (19-15), 8-3 | Astrodome (8-13) | 12-26 | |
| » Starters: Billy O'Dell vs Larry Dierker | Tenth | 14 out |
| Wednesday, May 24 |
| » Lost to Pirates (20-15), 7-4 | Astrodome (8-14) | 12-27 | |
| » Starters: Dennis Ribant vs Don Wilson | Tenth | 14½ out |
| Friday, May 26 |
| » Defeated Cubs (20-17), 17-4 | Wrigley Field (1-0) | 13-27 | |
| » Starters: Dave Giusti vs Ray Culp | Tenth | 13 out |
| Saturday, May 27 |
| » Defeated Cubs (20-18), 2-1 | Wrigley Field (2-0) | 14-27 | Won 2 |
| » Starters: Mike Cuellar vs Curt Simmons | Tenth | 13 out |
| Tuesday, May 30 |
| » Defeated Pirates (22-17), 3-2 | Forbes Field (1-0) | 15-27 | Won 3 |
| » Starters: Don Wilson vs Dennis Ribant | Tenth | 13 out |
| » Lost to Pirates (23-17), 4-3 | Forbes Field (1-1) | 15-28 | |
| » Starters: Larry Dierker vs Billy O'Dell | Tenth | 13 out |
| Wednesday, May 31 |
| » Defeated Mets (14-26), 6-1 | Astrodome (9-14) | 16-28 | |
| » Starters: Don Cardwell vs Dave Giusti | Ninth | 12 out |
| Future Astro Kenny Lofton is born in East Chicago, IN. |
| Thursday, June 1 |
| » Defeated Mets (14-27), 4-1 | Astrodome (10-14) | 17-28 | Won 2 |
| » Starters: Tom Seaver vs Mike Cuellar | Ninth | 12 out |
| Friday, June 2 |
| » Lost to Phillies (20-23), 5-3 | Astrodome (10-15) | 17-29 | |
| » Starters: Dick Ellsworth vs Chris Zachary | Ninth | 13 out |
| Saturday, June 3 |
| » Lost to Phillies (21-23), 4-2 | Astrodome (10-16) | 17-30 | Lost 2 |
| » Starters: Jim Bunning vs Larry Dierker | Ninth | 14 out |
| » Major-league debuts: Jose Herrera (Astros) |
| Sunday, June 4 |
| » Lost to Phillies (22-23), 6-1 | Astrodome (10-17) | 17-31 | Lost 3 |
| » Starters: Rick Wise vs Don Wilson | Ninth | 15 out |
| Future Astro Scott Servais is born in LaCrosse, WI. Future Astro Rick Wilkins is born in Jacksonville, FL. |
| Monday, June 5 |
| » Defeated Cardinals (27-18), 5-2 | Busch Stadium II (1-1) | 18-31 | |
| » Starters: Dave Giusti vs Larry Jaster | Ninth | 14½ out |
| Tuesday, June 6 |
| » Defeated Cardinals (27-19), 3-2 | Busch Stadium II (2-1) | 19-31 | Won 2 |
| » Starters: Mike Cuellar vs Ray Washburn | Eighth | 14½ out |
| Future Astro Ken Ramos is born in Sydney, NE. |
| Wednesday, June 7 |
| » Defeated Cardinals (27-20), 17-1 | Busch Stadium II (3-1) | 20-31 | Won 3 |
| » Starters: Bo Belinsky vs Steve Carlton | Ninth | 13½ out |
| Thursday, June 8 |
| » Lost to Cardinals (28-20), 6-2 | Busch Stadium II (3-2) | 20-32 | |
| » Starters: Larry Dierker vs Bob Gibson | Ninth | 13½ out |
| Friday, June 9 |
| » Lost to Reds (36-20), 10-7 | Crosley Field (1-3) | 20-33 | Lost 2 |
| » Starters: Don Wilson vs Jim Maloney | Ninth | 14½ out |
| Saturday, June 10 |
| » Lost to Reds (37-20), 9-4 | Crosley Field (1-4) | 20-34 | Lost 3 |
| » Starters: Dave Giusti vs Mel Queen | Ninth | 15½ out |
| Sunday, June 11 |
| » Defeated Reds (37-21), 7-4 | Crosley Field (2-4) | 21-34 | |
| » Starters: Mike Cuellar vs Milt Pappas | Ninth | 15½ out |
| » Lost to Reds (38-21), 8-4 | Crosley Field (2-5) | 21-35 | |
| » Starters: Bo Belinsky vs Sammy Ellis | Ninth | 15½ out |
| Monday, June 12 |
| » Defeated Giants (31-24), 5-2 | Astrodome (11-17) | 22-35 | |
| » Starters: Lindy McDaniel vs Larry Dierker | Eighth | 15 out |
| Tuesday, June 13 |
| » Lost to Giants (32-24), 6-2 | Astrodome (11-18) | 22-36 | |
| » Starters: Joe Gibbon vs Dave Giusti | Seventh | 15½ out |
| Wednesday, June 14 |
| » Defeated Giants (32-25), 7-4 | Astrodome (12-18) | 23-36 | |
| » Starters: Gaylord Perry vs Don Wilson | Seventh | 14½ out |
| Thursday, June 15 |
| » Defeated Giants (32-26), 6-2 | Astrodome (13-18) | 24-36 | Won 2 |
| » Starters: Bobby Bolin vs Mike Cuellar | Eighth | 14 out |
| Friday, June 16 |
| » Lost to Braves (30-28), 9-8 | Astrodome (13-19) | 24-37 | |
| » Starters: Denny Lemaster vs Bo Belinsky | Eighth | 15 out |
| Saturday, June 17 |
| » Lost to Braves (31-28), 3-1 | Astrodome (13-20) | 24-38 | Lost 2 |
| » Starters: Pat Jarvis vs Larry Dierker | Ninth | 14½ out |
| » Defeated Braves (31-29), 4-3 | Astrodome (14-20) | 25-38 | |
| » Starters: Tony Cloninger vs Dave Giusti | Ninth | 14½ out |
| Sunday, June 18 |
| » Defeated Braves (31-30), 2-0 | Astrodome (15-20) | 26-38 | Won 2 |
| » Starters: Phil Niekro vs Don Wilson | Eighth | 13 out |
| Monday, June 19 |
| » Lost to Cardinals (37-22), 5-4 | Astrodome (15-21) | 26-39 | |
| » Starters: Bob Gibson vs Mike Cuellar | Ninth | 14 out |
| Tuesday, June 20 |
| » Lost to Cardinals (38-22), 6-2 | Astrodome (15-22) | 26-40 | Lost 2 |
| » Starters: Larry Jaster vs Bo Belinsky | Eighth | 15 out |
| Wednesday, June 21 |
| » Lost to Reds (41-27), 3-2 | Astrodome (15-23) | 26-41 | Lost 3 |
| » Starters: Milt Pappas vs Larry Dierker | Ninth | 16 out |
| Friday, June 23 |
| » Lost to Cubs (35-28), 9-8 | Wrigley Field (2-1) | 26-42 | Lost 4 |
| » Starters: Dave Giusti vs Rich Nye | Ninth | 17½ out |
| Saturday, June 24 |
| » Lost to Cubs (36-28), 3-2 | Wrigley Field (2-2) | 26-43 | Lost 5 |
| » Starters: Mike Cuellar vs Fergie Jenkins | Ninth | 18½ out |
| Sunday, June 25 |
| » Lost to Cubs (37-28), 4-1 | Wrigley Field (2-3) | 26-44 | Lost 6 |
| » Starters: Don Wilson vs Bill Hands | Ninth | 18½ out |
| » Lost to Cubs (38-28), 8-0 | Wrigley Field (2-4) | 26-45 | Lost 7 |
| » Starters: Bo Belinsky vs Joe Niekro | Ninth | 18½ out |
| Tuesday, June 27 |
| » Lost to Braves (37-34), 13-5 | Atlanta-Fulton County Stadium (0-3) | 26-46 | Lost 8 |
| » Starters: Wade Blasingame vs Tony Cloninger | Ninth | 19 out |
| Wednesday, June 28 |
| » Defeated Braves (37-35), 4-2 | Atlanta-Fulton County Stadium (1-3) | 27-46 | |
| » Starters: Dave Giusti vs Phil Niekro | Tenth | 18 out |
| Friday, June 30 |
| » Lost to Dodgers (33-40), 5-4 | Astrodome (15-24) | 27-47 | |
| » Starters: Claude Osteen vs Don Wilson | Ninth | 18½ out |
| Saturday, July 1 |
| » Defeated Dodgers (33-41), 4-2 | Astrodome (16-24) | 28-47 | |
| » Starters: Don Sutton vs Bo Belinsky | Ninth | 17½ out |
| Sunday, July 2 |
| » Defeated Dodgers (33-42), 5-4 | Astrodome (17-24) | 29-47 | Won 2 |
| » Starters: Bill Singer vs Wade Blasingame | Eighth | 17 out |
| Tuesday, July 4 |
| » Lost to Phillies (37-38), 9-0 | Shibe Park (2-2) | 29-48 | |
| » Starters: Dave Giusti vs Chris Short | Tenth | 18 out |
| » Lost to Phillies (38-38), 4-3 | Shibe Park (2-3) | 29-49 | Lost 2 |
| » Starters: Don Wilson vs Jim Bunning | Tenth | 18 out |
| Future Astro Vinny Castilla is born in Oaxaca, Mexico. |
| Wednesday, July 5 |
| » Lost to Phillies (39-38), 3-2 | Shibe Park (2-4) | 29-50 | Lost 3 |
| » Starters: Mike Cuellar vs Rick Wise | Tenth | 18 out |
| Thursday, July 6 |
| » Defeated Cubs (46-33), 4-3 | Astrodome (18-24) | 30-50 | |
| » Starters: Fergie Jenkins vs Bo Belinsky | Tenth | 18 out |
| Friday, July 7 |
| » Defeated Cubs (46-34), 11-5 | Astrodome (19-24) | 31-50 | Won 2 |
| » Starters: Curt Simmons vs Wade Blasingame | Ninth | 18 out |
| Saturday, July 8 |
| » Defeated Cubs (46-35), 3-1 | Astrodome (20-24) | 32-50 | Won 3 |
| » Starters: Ray Culp vs Dave Giusti | Tenth | 18 out |
| Sunday, July 9 |
| » Defeated Cubs (46-36), 6-0 | Astrodome (21-24) | 33-50 | Won 4 |
| » Starters: Rich Nye vs Don Wilson | Ninth | 17 out |
| Tuesday, July 11 |
| Future Astro Donne Wall is born in Potosi, MO. |
| Thursday, July 13 |
| » Lost to Giants (46-38), 5-4 | Candlestick Park (0-5) | 33-51 | |
| » Starters: Bo Belinsky vs Ray Sadecki | Tenth | 17½ out |
| Friday, July 14 |
| » Defeated Giants (46-39), 8-6 | Candlestick Park (1-5) | 34-51 | |
| » Starters: Dave Giusti vs Juan Marichal | Ninth | 17½ out |
| Saturday, July 15 |
| » Lost to Giants (47-39), 3-1 | Candlestick Park (1-6) | 34-52 | |
| » Starters: Mike Cuellar vs Mike McCormick | Ninth | 17½ out |
| Sunday, July 16 |
| » Defeated Dodgers (36-49), 4-1 | Dodger Stadium (2-2) | 35-52 | |
| » Starters: Don Wilson vs Claude Osteen | Ninth | 15½ out |
| » Defeated Dodgers (36-50), 8-2 | Dodger Stadium (3-2) | 36-52 | Won 2 |
| » Starters: Wade Blasingame vs Jim Brewer | Ninth | 15½ out |
| Tuesday, July 18 |
| » Lost to Mets (35-51), 4-2 | Shea Stadium (0-2) | 36-53 | |
| » Starters: Bo Belinsky vs Bob Hendley | Tenth | 16 out |
| Wednesday, July 19 |
| » Lost to Mets (36-51), 8-4 | Shea Stadium (0-3) | 36-54 | Lost 2 |
| » Starters: Mike Cuellar vs Jack Fisher | Tenth | 17½ out |
| » Lost to Mets (37-51), 7-2 | Shea Stadium (0-4) | 36-55 | Lost 3 |
| » Starters: Dave Giusti vs Tom Seaver | Tenth | 17½ out |
| Thursday, July 20 |
| » Defeated Mets (37-52), 7-0 | Shea Stadium (1-4) | 37-55 | |
| » Starters: Don Wilson vs Dick Selma | Tenth | 17½ out |
| Friday, July 21 |
| » Lost to Pirates (45-44), 9-1 | Forbes Field (1-2) | 37-56 | |
| » Starters: Wade Blasingame vs Bob Veale | Tenth | 17½ out |
| Saturday, July 22 |
| » Lost to Pirates (46-44), 15-2 | Forbes Field (1-3) | 37-57 | Lost 2 |
| » Starters: Bo Belinsky vs Woodie Fryman | Ninth | 17½ out |
| Sunday, July 23 |
| » Defeated Pirates (46-45), 8-5 | Forbes Field (2-3) | 38-57 | |
| » Starters: Dave Giusti vs Steve Blass | Tenth | 18½ out |
| » Lost to Pirates (47-45), 15-2 | Forbes Field (2-4) | 38-58 | |
| » Starters: Barry Latman vs Tommie Sisk | Tenth | 18½ out |
| » Major-league debuts: Manny Sanguillen (Pirates) |
| Monday, July 24 |
| » Defeated Phillies (45-47), 2-1 | Astrodome (22-24) | 39-58 | |
| » Starters: Larry Jackson vs Mike Cuellar | Ninth | 17½ out |
| Tuesday, July 25 |
| » Lost to Phillies (46-47), 12-7 | Astrodome (22-25) | 39-59 | |
| » Starters: Jim Bunning vs Wade Blasingame | Tenth | 18½ out |
| Wednesday, July 26 |
| » Defeated Phillies (46-48), 3-2 | Astrodome (23-25) | 40-59 | |
| » Starters: Rick Wise vs Don Wilson | Tenth | 18½ out |
| Thursday, July 27 |
| » Defeated Pirates (48-48), 5-4 | Astrodome (24-25) | 41-59 | Won 2 |
| » Starters: Woodie Fryman vs Bo Belinsky | Tenth | 18 out |
| Friday, July 28 |
| » Defeated Pirates (48-49), 9-3 | Astrodome (25-25) | 42-59 | Won 3 |
| » Starters: Tommie Sisk vs Dave Giusti | Ninth | 18 out |
| Saturday, July 29 |
| » Defeated Pirates (48-50), 6-5 | Astrodome (26-25) | 43-59 | Won 4 |
| » Starters: Dennis Ribant vs Mike Cuellar | Ninth | 18 out |
| Sunday, July 30 |
| » Defeated Mets (39-59), 6-5 | Astrodome (27-25) | 44-59 | Won 5 |
| » Starters: Tom Seaver vs Wade Blasingame | Ninth | 17½ out |
| » Defeated Mets (39-60), 9-1 | Astrodome (28-25) | 45-59 | Won 6 |
| » Starters: Jack Fisher vs Don Wilson | Ninth | 17½ out |
| Monday, July 31 |
| » Defeated Mets (39-61), 3-2 | Astrodome (29-25) | 46-59 | Won 7 |
| » Starters: Dennis Bennett vs Bo Belinsky | Ninth | 17½ out |
| Tuesday, August 1 |
| » Lost to Mets (40-61), 5-1 | Astrodome (29-26) | 46-60 | |
| » Starters: Don Cardwell vs Dave Giusti | Ninth | 17½ out |
| Wednesday, August 2 |
| » Defeated Mets (40-62), 5-2 | Astrodome (30-26) | 47-60 | |
| » Starters: Bob Hendley vs Mike Cuellar | Ninth | 18 out |
| Friday, August 4 |
| » Lost to Phillies (51-51), 7-1 | Shibe Park (2-5) | 47-61 | |
| » Starters: Don Wilson vs Dick Ellsworth | Ninth | 19 out |
| Saturday, August 5 |
| » Lost to Phillies (52-51), 10-3 | Shibe Park (2-6) | 47-62 | Lost 2 |
| » Starters: Wade Blasingame vs John Boozer | Ninth | 20 out |
| Sunday, August 6 |
| » Lost to Phillies (53-51), 8-4 | Shibe Park (2-7) | 47-63 | Lost 3 |
| » Starters: Dave Giusti vs Larry Jackson | Ninth | 21 out |
| Tuesday, August 8 |
| » Lost to Reds (58-53), 5-0 | Crosley Field (2-6) | 47-64 | Lost 4 |
| » Starters: Mike Cuellar vs Milt Pappas | Ninth | 20½ out |
| Wednesday, August 9 |
| » Lost to Reds (59-53), 7-3 | Crosley Field (2-7) | 47-65 | Lost 5 |
| » Starters: Bo Belinsky vs Gary Nolan | Ninth | 21½ out |
| Thursday, August 10 |
| » Lost to Braves (57-51), 10-2 | Atlanta-Fulton County Stadium (1-4) | 47-66 | Lost 6 |
| » Starters: Don Wilson vs Pat Jarvis | Ninth | 21½ out |
| Future Astro Chuck Carr is born in San Bernardino, CA. |
| Friday, August 11 |
| » Lost to Braves (58-51), 6-5 | Atlanta-Fulton County Stadium (1-5) | 47-67 | Lost 7 |
| » Starters: Wade Blasingame vs Phil Niekro | Ninth | 22½ out |
| Saturday, August 12 |
| » Lost to Braves (59-51), 7-3 | Atlanta-Fulton County Stadium (1-6) | 47-68 | Lost 8 |
| » Starters: Dave Giusti vs Ken Johnson | Ninth | 24 out |
| » Lost to Braves (60-51), 2-0 | Atlanta-Fulton County Stadium (1-7) | 47-69 | Lost 9 |
| » Starters: Mike Cuellar vs Denny Lemaster | Ninth | 24 out |
| Sunday, August 13 |
| » Lost to Braves (61-51), 8-4 | Atlanta-Fulton County Stadium (1-8) | 47-70 | Lost 10 |
| » Starters: Bo Belinsky vs Ed Rakow | Tenth | 25 out |
| Tuesday, August 15 |
| » Defeated Dodgers (50-64), 2-1 | Astrodome (31-26) | 48-70 | |
| » Starters: Claude Osteen vs Bruce Von Hoff | Tenth | 25½ out |
| » Major-league debuts: Tom Dukes (Astros) |
| Wednesday, August 16 |
| » Lost to Dodgers (51-64), 7-1 | Astrodome (31-27) | 48-71 | |
| » Starters: Bill Singer vs Wade Blasingame | Tenth | 26½ out |
| Thursday, August 17 |
| » Defeated Dodgers (51-65), 4-0 | Astrodome (32-27) | 49-71 | |
| » Starters: Jim Brewer vs Dave Giusti | Tenth | 26 out |
| Friday, August 18 |
| » Lost to Cardinals (75-44), 5-3 | Astrodome (32-28) | 49-72 | |
| » Starters: Steve Carlton vs Mike Cuellar | Tenth | 27 out |
| Saturday, August 19 |
| » Lost to Cardinals (76-44), 7-4 | Astrodome (32-29) | 49-73 | Lost 2 |
| » Starters: Dick Hughes vs Bruce Von Hoff | Tenth | 28 out |
| Sunday, August 20 |
| » Defeated Cardinals (76-45), 2-1 | Astrodome (33-29) | 50-73 | |
| » Starters: Larry Jaster vs Don Wilson | Ninth | 27 out |
| Monday, August 21 |
| » Defeated Cardinals (76-46), 11-4 | Astrodome (34-29) | 51-73 | Won 2 |
| » Starters: Ray Washburn vs Wade Blasingame | Ninth | 26 out |
| Tuesday, August 22 |
| » Defeated Braves (62-58), 4-1 | Astrodome (35-29) | 52-73 | Won 3 |
| » Starters: Denny Lemaster vs Dave Giusti | Ninth | 26 out |
| Wednesday, August 23 |
| » Lost to Braves (63-58), 9-3 | Astrodome (35-30) | 52-74 | |
| » Starters: Clay Carroll vs Bruce Von Hoff | Ninth | 26 out |
| Thursday, August 24 |
| » Defeated Braves (63-59), 5-4 | Astrodome (36-30) | 53-74 | |
| » Starters: Pat Jarvis vs Bo Belinsky | Eighth | 26 out |
| Friday, August 25 |
| » Lost to Reds (68-59), 2-1 | Astrodome (36-31) | 53-75 | |
| » Starters: Mel Queen vs Don Wilson | Ninth | 26½ out |
| Saturday, August 26 |
| » Lost to Reds (69-59), 6-1 | Astrodome (36-32) | 53-76 | Lost 2 |
| » Starters: Jim Maloney vs Wade Blasingame | Ninth | 26 out |
| » Defeated Reds (69-60), 8-6 | Astrodome (37-32) | 54-76 | |
| » Starters: Milt Pappas vs Mike Cuellar | Ninth | 26 out |
| Sunday, August 27 |
| » Lost to Reds (70-60), 11-8 | Astrodome (37-33) | 54-77 | |
| » Starters: Sammy Ellis vs Dave Giusti | Ninth | 27 out |
| Monday, August 28 |
| » Lost to Cubs (70-61), 6-5 | Wrigley Field (2-5) | 54-78 | Lost 2 |
| » Starters: Bruce Von Hoff vs Fergie Jenkins | Eighth | 27½ out |
| Tuesday, August 29 |
| » Defeated Cubs (70-62), 5-3 | Wrigley Field (3-5) | 55-78 | |
| » Starters: Don Wilson vs Joe Niekro | Eighth | 26½ out |
| Wednesday, August 30 |
| » Lost to Cubs (71-62), 4-1 | Wrigley Field (3-6) | 55-79 | |
| » Starters: Mike Cuellar vs Bill Hands | Ninth | 27½ out |
| Thursday, August 31 |
| » Lost to Cardinals (83-51), 5-1 | Busch Stadium II (3-3) | 55-80 | Lost 2 |
| » Starters: Bo Belinsky vs Ray Washburn | Ninth | 28½ out |
| Friday, September 1 |
| » Lost to Cardinals (84-51), 5-0 | Busch Stadium II (3-4) | 55-81 | Lost 3 |
| » Starters: Bruce Von Hoff vs Nelson Briles | Ninth | 29½ out |
| Saturday, September 2 |
| » Lost to Cardinals (85-51), 8-2 | Busch Stadium II (3-5) | 55-82 | Lost 4 |
| » Starters: Dave Giusti vs Steve Carlton | Ninth | 30½ out |
| Sunday, September 3 |
| » Lost to Cardinals (86-51), 13-1 | Busch Stadium II (3-6) | 55-83 | Lost 5 |
| » Starters: Don Wilson vs Dick Hughes | Eighth | 31½ out |
| Future Astro Luis Gonzalez is born in Tampa, FL. |
| Monday, September 4 |
| » Lost to Giants (74-64), 4-3 | Astrodome (37-34) | 55-84 | Lost 6 |
| » Starters: Mike McCormick vs Mike Cuellar | Eighth | 31 out |
| Wednesday, September 6 |
| » Lost to Giants (75-64), 2-0 | Candlestick Park (1-7) | 55-85 | Lost 7 |
| » Starters: Dave Giusti vs Gaylord Perry | Ninth | 32 out |
| » Major-league debuts: Hal King (Astros) |
| Thursday, September 7 |
| » Lost to Giants (76-64), 3-2 | Candlestick Park (1-8) | 55-86 | Lost 8 |
| » Starters: Bruce Von Hoff vs Ron Herbel | Ninth | 33 out |
| » Major-league debuts: Dave Marshall (Giants) |
| Friday, September 8 |
| » Lost to Dodgers (64-75), 4-2 | Dodger Stadium (3-3) | 55-87 | Lost 9 |
| » Starters: Danny Coombs vs Don Sutton | Ninth | 33 out |
| Saturday, September 9 |
| » Defeated Dodgers (64-76), 5-3 | Dodger Stadium (4-3) | 56-87 | |
| » Starters: Mike Cuellar vs Claude Osteen | Ninth | 33 out |
| Sunday, September 10 |
| » Lost to Dodgers (65-76), 4-1 | Dodger Stadium (4-4) | 56-88 | |
| » Starters: Howie Reed vs Bill Singer | Ninth | 32½ out |
| » Defeated Dodgers (65-77), 1-0 | Dodger Stadium (5-4) | 57-88 | |
| » Starters: Bo Belinsky vs Jim Brewer | Ninth | 32½ out |
| Monday, September 11 |
| » Defeated Cubs (79-69), 11-10 | Astrodome (38-34) | 58-88 | Won 2 |
| » Starters: Bill Hands vs Dave Giusti | Ninth | 32½ out |
| Tuesday, September 12 |
| » Defeated Cubs (79-70), 5-4 | Astrodome (39-34) | 59-88 | Won 3 |
| » Starters: Joe Niekro vs Bruce Von Hoff | Ninth | 32½ out |
| Future Astro Pat Listach is born in Natchitoches, LA. |
| Thursday, September 14 |
| Former Astro Walt Bond dies in Houston, TX at the age of 30. |
| Saturday, September 16 |
| » Defeated Mets (55-92), 6-1 | Astrodome (40-34) | 60-88 | Won 4 |
| » Starters: Tug McGraw vs Mike Cuellar | Ninth | 32½ out |
| Sunday, September 17 |
| » Defeated Mets (55-93), 4-3 | Astrodome (41-34) | 61-88 | Won 5 |
| » Starters: Jerry Koosman vs Don Wilson | Ninth | 32½ out |
| Monday, September 18 |
| » Defeated Pirates (75-76), 14-4 | Astrodome (42-34) | 62-88 | Won 6 |
| » Starters: Tommie Sisk vs Dave Giusti | Ninth | 32½ out |
| » Major-league debuts: Bob Robertson (Pirates) |
| Tuesday, September 19 |
| » Lost to Pirates (76-76), 11-7 | Astrodome (42-35) | 62-89 | |
| » Starters: Bob Moose vs Bruce Von Hoff | Ninth | 33½ out |
| » Major-league debuts: Bob Moose (Pirates) |
| Wednesday, September 20 |
| » Defeated Pirates (76-77), 5-4 | Astrodome (43-35) | 63-89 | |
| » Starters: Bruce Dal Canton vs Howie Reed | Ninth | 32½ out |
| Thursday, September 21 |
| » Major-league debuts: Dave Leonhard (Orioles) |
| Friday, September 22 |
| » Defeated Mets (57-95), 8-0 | Shea Stadium (2-4) | 64-89 | Won 2 |
| » Starters: Mike Cuellar vs Jerry Koosman | Ninth | 32½ out |
| » Lost to Mets (58-95), 8-5 | Shea Stadium (2-5) | 64-90 | |
| » Starters: Wade Blasingame vs Tug McGraw | Ninth | 32½ out |
| Saturday, September 23 |
| » Lost to Mets (59-95), 1-0 | Shea Stadium (2-6) | 64-91 | Lost 2 |
| » Starters: Dave Giusti vs Tom Seaver | Eighth | 32½ out |
| Sunday, September 24 |
| » Defeated Mets (59-96), 4-2 | Shea Stadium (3-6) | 65-91 | |
| » Starters: Chris Zachary vs Les Rohr | Ninth | 32½ out |
| Monday, September 25 |
| » Defeated Phillies (80-75), 4-3 | Astrodome (44-35) | 66-91 | Won 2 |
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