| 1980-04-09 | @ CIN | 1 | L 0-9 | 0-1 | 2 | 51,774 | Phil Niekro | Frank Pastore | Frank Pastore | Phil Niekro | | 0 | 9 | -9 |
| 1980-04-11 | @ CIN | 2 | L 0-6 | 0-2 | 4 | 12,902 | Larry McWilliams | Mike LaCoss | Mike LaCoss | Larry McWilliams | | 0 | 15 | -15 |
| 1980-04-12 | @ CIN | 3 | L 4-5 | 0-3 | 5 | 11,839 | Rick Matula | Bill Bonham | Tom Hume | Al Hrabosky | | 4 | 20 | -16 |
| 1980-04-13 | @ CIN | 4 | L 0-5 | 0-4 | 6 | 32,996 | Phil Niekro | Charlie Leibrandt | Charlie Leibrandt | Phil Niekro | | 4 | 25 | -21 |
| 1980-04-14 | @ HOU | 5 | L 4-5 | 0-5 | 6 | 15,017 | Doyle Alexander | J.R. Richard | Joe Sambito | Gene Garber | | 8 | 30 | -22 |
| 1980-04-15 | @ HOU | 6 | L 2-6 | 0-6 | 6 | 15,712 | Larry McWilliams | Joe Niekro | Joe Niekro | Larry McWilliams | | 10 | 36 | -26 |
| 1980-04-17 | vs CIN | 7 | L 1-4 | 0-7 | 6 | 15,742 | Phil Niekro | Frank Pastore | Frank Pastore | Phil Niekro | | 11 | 40 | -29 |
| 1980-04-18 | vs CIN | 8 | W 3-0 | 1-7 | 6 | 5,624 | Rick Matula | Charlie Leibrandt | Rick Matula | Charlie Leibrandt | | 14 | 40 | -26 |
| 1980-04-19 | vs CIN | 9 | L 1-6 | 1-8 | 6 | 9,684 | Doyle Alexander | Bill Bonham | Bill Bonham | Doyle Alexander | | 15 | 46 | -31 |
| 1980-04-20 | vs CIN | 10 | L 3-5 | 1-9 | 6 | 8,002 | Tommy Boggs | Tom Seaver | Dave Tomlin | Larry Bradford | Tom Hume | 18 | 51 | -33 |
| 1980-04-22 | vs SDN | 11 | W 3-2 | 2-9 | 6 | 4,710 | Phil Niekro | John Curtis | Al Hrabosky | Bob Shirley | | 21 | 53 | -32 |
| 1980-04-23 | vs SDN | 12 | W 2-1 | 3-9 | 6 | 4,166 | Rick Matula | Randy Jones | Rick Matula | Randy Jones | Al Hrabosky | 23 | 54 | -31 |
| 1980-04-24 | vs SDN | 13 | W 8-7 | 4-9 | 5 | 4,498 | Doyle Alexander | Eric Rasmussen | Gene Garber | Rollie Fingers | | 31 | 61 | -30 |
| 1980-04-25 | vs MON | 14 | W 8-7 | 5-9 | 5 | 6,929 | Tommy Boggs | Bill Lee | Larry Bradford | Stan Bahnsen | | 39 | 68 | -29 |
| 1980-04-26 | vs MON | 15 | L 3-4 | 5-10 | 6 | 13,705 | Phil Niekro | Ross Grimsley | Ross Grimsley | Phil Niekro | Woodie Fryman | 42 | 72 | -30 |
| 1980-04-27 | vs MON | 16 | W 6-3 | 6-10 | 4 | 12,917 | Larry McWilliams | Scott Sanderson | Larry McWilliams | Scott Sanderson | Al Hrabosky | 48 | 75 | -27 |
| 1980-04-30 | @ SDN | 17 | L 1-2 | 6-11 | 5 | 9,018 | Rick Matula | Eric Rasmussen | Eric Rasmussen | Rick Matula | Bob Shirley | 49 | 77 | -28 |
| 1980-05-01 | @ SDN | 18 | L 3-4 | 6-12 | 5 | 12,131 | Doyle Alexander | Randy Jones | Bob Shirley | Rick Camp | | 52 | 81 | -29 |
| 1980-05-02 | @ PIT | 19 | W 6-1 | 7-12 | 5 | 11,476 | Phil Niekro | Jim Rooker | Phil Niekro | Jim Rooker | | 58 | 82 | -24 |
| 1980-05-03 | @ PIT | 20 | W 3-1 | 8-12 | 5 | 34,104 | Larry McWilliams | Don Robinson | Al Hrabosky | Grant Jackson | | 61 | 83 | -22 |
| 1980-05-04 | @ PIT | 21 | L 4-13 | 8-13 | 5 | 14,358 | Tommy Boggs | Jim Bibby | Jim Bibby | Tommy Boggs | | 65 | 96 | -31 |
| 1980-05-05 | @ PHI | 22 | L 1-7 | 8-14 | 5 | 26,165 | Rick Matula | Steve Carlton | Steve Carlton | Rick Matula | | 66 | 103 | -37 |
| 1980-05-06 | @ PHI | 23 | L 5-10 | 8-15 | 5 | 25,302 | Doyle Alexander | Dick Ruthven | Dick Ruthven | Doyle Alexander | Dickie Noles | 71 | 113 | -42 |
| 1980-05-09 | vs HOU | 24 | W 5-4 | 9-15 | 5 | 11,111 | Larry McWilliams | Ken Forsch | Larry McWilliams | Ken Forsch | Larry Bradford | 76 | 117 | -41 |
| 1980-05-10 | vs HOU | 25 | L 2-3 | 9-16 | 5 | 13,798 | Rick Matula | J.R. Richard | Frank LaCorte | Gene Garber | Joe Sambito | 78 | 120 | -42 |
| 1980-05-11 | vs HOU | 26 | W 7-4 | 10-16 | 5 | 10,871 | Phil Niekro | Joe Niekro | Phil Niekro | Joe Niekro | | 85 | 124 | -39 |
| 1980-05-13 | vs PHI | 27 | W 7-3 | 11-16 | 5 | 10,146 | Doyle Alexander | Randy Lerch | Doyle Alexander | Randy Lerch | Rick Camp | 92 | 127 | -35 |
| 1980-05-14 | vs PHI | 28 | L 1-9 | 11-17 | 5 | 4,625 | Larry McWilliams | Steve Carlton | Steve Carlton | Larry McWilliams | | 93 | 136 | -43 |
| 1980-05-16 | vs NYN | 29 | L 3-5 | 11-18 | 5 | 6,135 | Phil Niekro | Pete Falcone | Pete Falcone | Phil Niekro | Neil Allen | 96 | 141 | -45 |
| 1980-05-18 | vs NYN | 30 | W 2-1 | 12-19 | 6 | 0 | Rick Matula | Pat Zachry | Rick Matula | Pat Zachry | Rick Camp | 98 | 142 | -44 |
| 1980-05-18 | vs NYN | 31 | L 1-2 | 12-19 | 6 | 11,807 | Doyle Alexander | Ray Burris | Neil Allen | Gene Garber | | 99 | 144 | -45 |
| 1980-05-19 | @ MON | 32 | L 8-11 | 12-20 | 6 | 20,656 | Larry McWilliams | David Palmer | David Palmer | Larry McWilliams | Woodie Fryman | 107 | 155 | -48 |
| 1980-05-20 | @ MON | 33 | W 1-0 | 13-20 | 6 | 11,071 | Phil Niekro | Scott Sanderson | Phil Niekro | Scott Sanderson | | 108 | 155 | -47 |
| 1980-05-21 | @ MON | 34 | L 2-3 | 13-21 | 6 | 13,606 | Preston Hanna | Steve Rogers | Steve Rogers | Gene Garber | | 110 | 158 | -48 |
| 1980-05-23 | @ NYN | 35 | L 1-2 | 13-22 | 6 | 7,864 | Rick Matula | Ray Burris | Ray Burris | Rick Matula | Neil Allen | 111 | 160 | -49 |
| 1980-05-24 | @ NYN | 36 | L 4-5 | 13-23 | 6 | 7,221 | Doyle Alexander | Pat Zachry | Neil Allen | Rick Camp | | 115 | 165 | -50 |
| 1980-05-25 | @ NYN | 37 | L 0-3 | 13-24 | 6 | 13,624 | Phil Niekro | Craig Swan | Craig Swan | Phil Niekro | | 115 | 168 | -53 |
| 1980-05-26 | vs SFN | 38 | W 2-1 | 14-24 | 6 | 5,822 | Tommy Boggs | Allen Ripley | Tommy Boggs | Greg Minton | Larry Bradford | 117 | 169 | -52 |
| 1980-05-27 | vs SFN | 39 | W 6-3 | 15-24 | 6 | 5,277 | Larry McWilliams | Bob Knepper | Larry McWilliams | Bob Knepper | Gene Garber | 123 | 172 | -49 |
| 1980-05-28 | vs SFN | 40 | W 3-2 | 16-24 | 6 | 5,500 | Doyle Alexander | Ed Whitson | Al Hrabosky | Gary Lavelle | | 126 | 174 | -48 |
| 1980-05-29 | @ LAN | 41 | L 0-3 | 16-25 | 6 | 24,630 | Phil Niekro | Bob Welch | Bob Welch | Phil Niekro | | 126 | 177 | -51 |
| 1980-05-30 | @ LAN | 42 | L 4-8 | 16-26 | 6 | 32,200 | Rick Matula | Burt Hooton | Burt Hooton | Rick Matula | | 130 | 185 | -55 |
| 1980-05-31 | @ LAN | 43 | W 6-5 | 17-26 | 6 | 40,161 | Tommy Boggs | Jerry Reuss | Tommy Boggs | Jerry Reuss | Gene Garber | 136 | 190 | -54 |
| 1980-06-01 | @ LAN | 44 | W 9-5 | 18-26 | 6 | 49,320 | Doyle Alexander | Dave Goltz | Doyle Alexander | Dave Goltz | Rick Camp | 145 | 195 | -50 |
| 1980-06-02 | @ SFN | 45 | W 4-2 | 19-26 | 5 | 3,768 | Phil Niekro | Ed Whitson | Phil Niekro | Ed Whitson | | 149 | 197 | -48 |
| 1980-06-03 | @ SFN | 46 | L 2-3 | 19-27 | 6 | 9,294 | Larry McWilliams | Vida Blue | Greg Minton | Larry Bradford | | 151 | 200 | -49 |
| 1980-06-04 | @ SFN | 47 | W 7-2 | 20-27 | 5 | 5,593 | Rick Matula | John Montefusco | Rick Matula | John Montefusco | | 158 | 202 | -44 |
| 1980-06-06 | vs LAN | 48 | L 0-5 | 20-28 | 5 | 18,331 | Phil Niekro | Jerry Reuss | Jerry Reuss | Phil Niekro | | 158 | 207 | -49 |
| 1980-06-07 | vs LAN | 49 | W 6-1 | 21-28 | 5 | 25,723 | Doyle Alexander | Dave Goltz | Doyle Alexander | Dave Goltz | | 164 | 208 | -44 |
| 1980-06-08 | vs LAN | 50 | L 1-3 | 21-29 | 5 | 12,543 | Tommy Boggs | Don Sutton | Don Sutton | Tommy Boggs | Rick Sutcliffe | 165 | 211 | -46 |
| 1980-06-09 | vs SLN | 51 | L 5-8 | 21-30 | 5 | 6,513 | Rick Matula | Jim Kaat | John Littlefield | Larry Bradford | George Frazier | 170 | 219 | -49 |
| 1980-06-10 | vs SLN | 52 | W 5-2 | 22-30 | 5 | 6,763 | Phil Niekro | Bob Sykes | Phil Niekro | Bob Sykes | | 175 | 221 | -46 |
| 1980-06-11 | vs SLN | 53 | L 3-4 | 22-31 | 5 | 6,755 | Larry McWilliams | Bob Forsch | Bob Forsch | Larry Bradford | Kim Seaman | 178 | 225 | -47 |
| 1980-06-13 | @ CHN | 54 | W 7-6 | 23-31 | 4 | 14,470 | Doyle Alexander | Lynn McGlothen | Doyle Alexander | Lynn McGlothen | Gene Garber | 185 | 231 | -46 |
| 1980-06-14 | @ CHN | 55 | L 5-10 | 23-32 | 4 | 25,108 | Phil Niekro | Dennis Lamp | Dennis Lamp | Phil Niekro | | 190 | 241 | -51 |
| 1980-06-15 | @ CHN | 56 | L 1-4 | 23-33 | 5 | 11,421 | Rick Matula | Mike Krukow | Mike Krukow | Rick Matula | Bruce Sutter | 191 | 245 | -54 |
| 1980-06-16 | @ SLN | 57 | W 6-3 | 24-33 | 5 | 16,809 | Tommy Boggs | Bob Forsch | Tommy Boggs | Bob Forsch | | 197 | 248 | -51 |
| 1980-06-17 | @ SLN | 58 | L 2-3 | 24-34 | 6 | 13,524 | Doyle Alexander | Pete Vuckovich | Pete Vuckovich | Doyle Alexander | | 199 | 251 | -52 |
| 1980-06-18 | vs PIT | 59 | W 3-2 | 26-34 | 5 | 0 | Larry McWilliams | Eddie Solomon | Gene Garber | Kent Tekulve | | 202 | 253 | -51 |
| 1980-06-18 | vs PIT | 60 | W 5-4 | 26-34 | 5 | 17,154 | Phil Niekro | Rick Rhoden | Rick Camp | Enrique Romo | Gene Garber | 207 | 257 | -50 |
| 1980-06-19 | vs PIT | 61 | W 4-3 | 27-34 | 5 | 10,585 | Rick Matula | Don Robinson | Rick Matula | Don Robinson | Larry Bradford | 211 | 260 | -49 |
| 1980-06-20 | vs CHN | 62 | L 2-4 | 27-35 | 6 | 10,273 | Tommy Boggs | Lynn McGlothen | Lynn McGlothen | Tommy Boggs | Bruce Sutter | 213 | 264 | -51 |
| 1980-06-21 | vs CHN | 63 | W 8-0 | 28-35 | 5 | 14,516 | Doyle Alexander | Guillermo Hernandez | Doyle Alexander | Guillermo Hernandez | | 221 | 264 | -43 |
| 1980-06-22 | vs CHN | 64 | L 2-3 | 28-36 | 5 | 15,070 | Phil Niekro | Dennis Lamp | Dennis Lamp | Phil Niekro | Dick Tidrow | 223 | 267 | -44 |
| 1980-06-24 | @ CIN | 65 | L 2-8 | 28-37 | 6 | 22,682 | Larry McWilliams | Charlie Leibrandt | Charlie Leibrandt | Larry McWilliams | | 225 | 275 | -50 |
| 1980-06-25 | @ CIN | 66 | L 3-15 | 28-38 | 6 | 32,603 | Rick Matula | Tom Seaver | Tom Seaver | Rick Matula | | 228 | 290 | -62 |
| 1980-06-27 | @ SDN | 67 | W 5-3 | 29-38 | 5 | 15,303 | Doyle Alexander | John Curtis | Rick Camp | John Curtis | Gene Garber | 233 | 293 | -60 |
| 1980-06-28 | @ SDN | 68 | W 5-4 | 30-39 | 5 | 0 | Tommy Boggs | Gary Lucas | Larry Bradford | Bob Shirley | Gene Garber | 238 | 297 | -59 |
| 1980-06-28 | @ SDN | 69 | L 2-3 | 30-39 | 5 | 17,554 | Phil Niekro | Dennis Blair | John D'Acquisto | Rick Camp | | 240 | 300 | -60 |
| 1980-06-29 | @ SDN | 70 | W 4-2 | 31-39 | 5 | 11,938 | Larry McWilliams | Eric Rasmussen | Larry McWilliams | Eric Rasmussen | | 244 | 302 | -58 |
| 1980-06-30 | vs HOU | 71 | W 5-4 | 32-39 | 5 | 8,208 | Rick Matula | Ken Forsch | Al Hrabosky | Joe Sambito | | 249 | 306 | -57 |
| 1980-07-01 | vs HOU | 72 | W 13-4 | 33-39 | 5 | 9,546 | Doyle Alexander | Joe Niekro | Doyle Alexander | Joe Niekro | | 262 | 310 | -48 |
| 1980-07-02 | vs HOU | 73 | W 14-0 | 34-39 | 4 | 21,908 | Phil Niekro | Vern Ruhle | Phil Niekro | Vern Ruhle | | 276 | 310 | -34 |
| 1980-07-03 | vs HOU | 74 | L 3-5 | 34-40 | 5 | 15,769 | Tommy Boggs | J.R. Richard | J.R. Richard | Tommy Boggs | Frank LaCorte | 279 | 315 | -36 |
| 1980-07-04 | vs SDN | 75 | W 9-0 | 35-40 | 4 | 46,071 | Larry McWilliams | Eric Rasmussen | Larry McWilliams | Eric Rasmussen | | 288 | 315 | -27 |
| 1980-07-05 | vs SDN | 76 | W 3-2 | 36-40 | 4 | 18,932 | Rick Matula | Juan Eichelberger | Rick Matula | Rollie Fingers | | 291 | 317 | -26 |
| 1980-07-06 | vs SDN | 77 | W 6-5 | 37-40 | 4 | 14,302 | Doyle Alexander | Steve Mura | Doyle Alexander | Bob Shirley | Phil Niekro | 297 | 322 | -25 |
| 1980-07-10 | vs CIN | 78 | L 6-8 | 37-41 | 4 | 19,177 | Phil Niekro | Charlie Leibrandt | Paul Moskau | Phil Niekro | | 303 | 330 | -27 |
| 1980-07-11 | vs CIN | 79 | L 3-5 | 37-42 | 5 | 26,139 | Doyle Alexander | Mario Soto | Mario Soto | Doyle Alexander | Tom Hume | 306 | 335 | -29 |
| 1980-07-12 | @ HOU | 80 | L 5-9 | 37-43 | 5 | 38,610 | Larry McWilliams | Joe Niekro | Joe Niekro | Larry McWilliams | Dave Smith | 311 | 344 | -33 |
| 1980-07-13 | @ HOU | 81 | L 5-6 | 37-45 | 5 | 0 | Rick Matula | Joaquin Andujar | Joe Sambito | Gene Garber | Frank LaCorte | 316 | 350 | -34 |
| 1980-07-13 | @ HOU | 82 | L 1-6 | 37-45 | 5 | 31,230 | Tommy Boggs | Vern Ruhle | Vern Ruhle | Tommy Boggs | | 317 | 356 | -39 |
| 1980-07-14 | @ HOU | 83 | W 2-0 | 38-45 | 5 | 20,247 | Phil Niekro | J.R. Richard | Phil Niekro | Gordie Pladson | | 319 | 356 | -37 |
| 1980-07-15 | vs NYN | 84 | L 2-9 | 38-46 | 5 | 21,608 | Doyle Alexander | Pat Zachry | Pat Zachry | Doyle Alexander | | 321 | 365 | -44 |
| 1980-07-16 | vs NYN | 85 | W 5-2 | 39-46 | 5 | 5,414 | Larry McWilliams | Craig Swan | Larry McWilliams | Craig Swan | | 326 | 367 | -41 |
| 1980-07-17 | vs NYN | 86 | L 0-6 | 39-47 | 5 | 7,107 | Rick Matula | John Pacella | John Pacella | Rick Matula | | 326 | 373 | -47 |
| 1980-07-18 | vs PHI | 87 | L 2-7 | 39-48 | 5 | 13,908 | Phil Niekro | Nino Espinosa | Nino Espinosa | Phil Niekro | Dickie Noles | 328 | 380 | -52 |
| 1980-07-19 | vs PHI | 88 | W 5-2 | 41-48 | 5 | 0 | Doyle Alexander | Dick Ruthven | Doyle Alexander | Dick Ruthven | | 333 | 382 | -49 |
| 1980-07-19 | vs PHI | 89 | W 7-2 | 41-48 | 5 | 35,524 | Tommy Boggs | Dan Larson | Tommy Boggs | Dan Larson | Rick Camp | 340 | 384 | -44 |
| 1980-07-20 | vs PHI | 90 | W 3-2 | 42-48 | 5 | 9,335 | Larry McWilliams | Bob Walk | Larry McWilliams | Bob Walk | | 343 | 386 | -43 |
| 1980-07-21 | vs MON | 91 | L 6-8 | 42-49 | 5 | 6,894 | Rick Matula | Scott Sanderson | Scott Sanderson | Rick Matula | Elias Sosa | 349 | 394 | -45 |
| 1980-07-22 | vs MON | 92 | W 7-5 | 43-49 | 5 | 37,108 | Phil Niekro | Bill Lee | Phil Niekro | Stan Bahnsen | Rick Camp | 356 | 399 | -43 |
| 1980-07-23 | vs MON | 93 | W 6-5 | 44-49 | 5 | 10,873 | Doyle Alexander | Charlie Lea | Rick Camp | Bill Gullickson | | 362 | 404 | -42 |
| 1980-07-25 | @ PHI | 94 | L 4-5 | 45-50 | 5 | 0 | Larry McWilliams | Dick Ruthven | Dick Ruthven | Rick Camp | | 366 | 409 | -43 |
| 1980-07-25 | @ PHI | 95 | W 3-0 | 45-50 | 5 | 38,408 | Tommy Boggs | Dan Larson | Tommy Boggs | Dan Larson | | 369 | 409 | -40 |
| 1980-07-26 | @ PHI | 96 | L 3-6 | 45-51 | 5 | 33,112 | Phil Niekro | Bob Walk | Bob Walk | Phil Niekro | Ron Reed | 372 | 415 | -43 |
| 1980-07-27 | @ PHI | 97 | L 4-17 | 45-52 | 5 | 35,249 | Rick Matula | Steve Carlton | Steve Carlton | Rick Matula | | 376 | 432 | -56 |
| 1980-07-28 | @ NYN | 98 | W 6-3 | 46-52 | 5 | 12,737 | Doyle Alexander | Pete Falcone | Doyle Alexander | Pete Falcone | | 382 | 435 | -53 |
| 1980-07-29 | @ NYN | 99 | L 1-2 | 46-53 | 5 | 9,512 | Larry McWilliams | Mark Bomback | Mark Bomback | Larry McWilliams | Neil Allen | 383 | 437 | -54 |
| 1980-07-30 | @ NYN | 100 | L 0-3 | 46-54 | 5 | 16,561 | Tommy Boggs | Pat Zachry | Pat Zachry | Tommy Boggs | | 383 | 440 | -57 |
| 1980-08-01 | @ MON | 101 | L 1-4 | 46-55 | 5 | 30,168 | Phil Niekro | Scott Sanderson | Scott Sanderson | Phil Niekro | | 384 | 444 | -60 |
| 1980-08-02 | @ MON | 102 | L 1-5 | 46-56 | 5 | 41,785 | Doyle Alexander | Fred Norman | Fred Norman | Doyle Alexander | | 385 | 449 | -64 |
| 1980-08-03 | @ MON | 103 | L 5-6 | 46-57 | 6 | 38,356 | Larry McWilliams | Charlie Lea | Charlie Lea | Larry McWilliams | Elias Sosa | 390 | 455 | -65 |
| 1980-08-04 | vs LAN | 104 | L 3-5 | 46-58 | 5 | 30,330 | Tommy Boggs | Jerry Reuss | Jerry Reuss | Tommy Boggs | Don Stanhouse | 393 | 460 | -67 |
| 1980-08-05 | vs LAN | 105 | W 6-4 | 47-58 | 5 | 10,187 | Phil Niekro | Dave Goltz | Rick Camp | Don Stanhouse | | 399 | 464 | -65 |
| 1980-08-06 | vs LAN | 106 | L 2-6 | 47-59 | 5 | 9,441 | Rick Matula | Don Sutton | Don Sutton | Rick Matula | Bobby Castillo | 401 | 470 | -69 |
| 1980-08-07 | vs LAN | 107 | W 4-3 | 48-59 | 5 | 10,056 | Doyle Alexander | Bob Welch | Doyle Alexander | Bob Welch | Rick Camp | 405 | 473 | -68 |
| 1980-08-08 | vs SFN | 108 | W 7-3 | 49-59 | 5 | 9,014 | Larry McWilliams | Allen Ripley | Larry McWilliams | Greg Minton | | 412 | 476 | -64 |
| 1980-08-09 | vs SFN | 109 | L 4-5 | 49-60 | 5 | 17,906 | Tommy Boggs | Bob Knepper | Al Holland | Tommy Boggs | Greg Minton | 416 | 481 | -65 |
| 1980-08-10 | vs SFN | 110 | W 3-1 | 50-60 | 5 | 9,027 | Phil Niekro | Alan Hargesheimer | Phil Niekro | Alan Hargesheimer | Rick Camp | 419 | 482 | -63 |
| 1980-08-11 | @ LAN | 111 | W 3-2 | 51-60 | 5 | 32,118 | Rick Matula | Don Sutton | Rick Matula | Don Sutton | Rick Camp | 422 | 484 | -62 |
| 1980-08-12 | @ LAN | 112 | W 7-6 | 52-60 | 5 | 35,905 | Doyle Alexander | Bob Welch | Gene Garber | Rick Sutcliffe | Rick Camp | 429 | 490 | -61 |
| 1980-08-13 | @ LAN | 113 | W 2-0 | 53-60 | 5 | 36,345 | Tommy Boggs | Burt Hooton | Tommy Boggs | Burt Hooton | | 431 | 490 | -59 |
| 1980-08-14 | @ SFN | 114 | L 1-5 | 53-61 | 5 | 5,448 | Larry McWilliams | Alan Hargesheimer | Alan Hargesheimer | Larry McWilliams | Greg Minton | 432 | 495 | -63 |
| 1980-08-15 | @ SFN | 115 | W 8-2 | 54-61 | 5 | 10,556 | Phil Niekro | Ed Whitson | Gene Garber | Gary Lavelle | | 440 | 497 | -57 |
| 1980-08-16 | @ SFN | 116 | L 1-2 | 54-62 | 5 | 14,634 | Rick Matula | Vida Blue | Vida Blue | Rick Matula | | 441 | 499 | -58 |
| 1980-08-17 | @ SFN | 117 | W 8-2 | 55-62 | 5 | 21,029 | Doyle Alexander | Allen Ripley | Doyle Alexander | Allen Ripley | | 449 | 501 | -52 |
| 1980-08-19 | vs CHN | 118 | W 5-4 | 56-62 | 5 | 9,485 | Tommy Boggs | Dennis Lamp | Phil Niekro | Dick Tidrow | | 454 | 505 | -51 |
| 1980-08-20 | vs CHN | 119 | W 9-5 | 57-62 | 5 | 7,549 | Larry McWilliams | Lynn McGlothen | Larry McWilliams | Lynn McGlothen | | 463 | 510 | -47 |
| 1980-08-21 | vs CHN | 120 | W 6-4 | 58-62 | 5 | 9,617 | Phil Niekro | Mike Krukow | Phil Niekro | Mike Krukow | Rick Camp | 469 | 514 | -45 |
| 1980-08-22 | vs SLN | 121 | L 4-7 | 58-63 | 5 | 11,854 | Rick Matula | John Fulgham | John Fulgham | Rick Matula | | 473 | 521 | -48 |
| 1980-08-23 | vs SLN | 122 | W 7-2 | 59-63 | 5 | 21,099 | Doyle Alexander | Pete Vuckovich | Doyle Alexander | Pete Vuckovich | | 480 | 523 | -43 |
| 1980-08-24 | vs SLN | 123 | W 10-5 | 60-63 | 5 | 12,512 | Tommy Boggs | Silvio Martinez | Tommy Boggs | Silvio Martinez | | 490 | 528 | -38 |
| 1980-08-25 | @ PIT | 124 | W 8-6 | 61-63 | 5 | 15,657 | Larry McWilliams | Jim Bibby | Preston Hanna | Jim Bibby | Larry Bradford | 498 | 534 | -36 |
| 1980-08-26 | @ PIT | 125 | W 4-2 | 62-63 | 4 | 14,695 | Phil Niekro | Bert Blyleven | Gene Garber | Kent Tekulve | | 502 | 536 | -34 |
| 1980-08-27 | @ PIT | 126 | W 7-4 | 63-63 | 4 | 12,363 | Rick Matula | Don Robinson | Rick Matula | Don Robinson | Al Hrabosky | 509 | 540 | -31 |
| 1980-08-28 | @ SLN | 127 | L 2-11 | 63-64 | 5 | 7,203 | Doyle Alexander | Bob Forsch | Bob Forsch | Doyle Alexander | | 511 | 551 | -40 |
| 1980-08-29 | @ SLN | 128 | W 4-3 | 64-64 | 5 | 11,551 | Tommy Boggs | Silvio Martinez | Tommy Boggs | Silvio Martinez | Rick Camp | 515 | 554 | -39 |
| 1980-08-30 | @ SLN | 129 | L 3-5 | 64-65 | 5 | 19,681 | Larry McWilliams | Don Hood | Don Hood | Larry McWilliams | John Urrea | 518 | 559 | -41 |
| 1980-08-31 | @ SLN | 130 | W 6-2 | 65-65 | 5 | 27,821 | Phil Niekro | Bob Sykes | Phil Niekro | Jim Otten | | 524 | 561 | -37 |
| 1980-09-01 | @ CHN | 131 | W 5-2 | 66-65 | 4 | 11,647 | Rick Matula | Dennis Lamp | Rick Matula | Dennis Lamp | Rick Camp | 529 | 563 | -34 |
| 1980-09-02 | @ CHN | 132 | W 10-5 | 67-65 | 4 | 4,013 | Doyle Alexander | Mike Krukow | Doyle Alexander | Mike Krukow | | 539 | 568 | -29 |
| 1980-09-03 | @ CHN | 133 | W 4-3 | 68-65 | 4 | 1,480 | Tommy Boggs | Lynn McGlothen | Tommy Boggs | Lynn McGlothen | Rick Camp | 543 | 571 | -28 |
| 1980-09-05 | vs PIT | 134 | W 7-4 | 69-65 | 4 | 29,610 | Larry McWilliams | Jim Bibby | Rick Camp | Kent Tekulve | | 550 | 575 | -25 |
| 1980-09-06 | vs PIT | 135 | W 3-2 | 70-65 | 4 | 17,821 | Phil Niekro | Bert Blyleven | Phil Niekro | Bert Blyleven | Gene Garber | 553 | 577 | -24 |
| 1980-09-07 | vs PIT | 136 | W 6-5 | 71-65 | 4 | 19,762 | Rick Matula | Rick Rhoden | Larry Bradford | Kent Tekulve | Rick Camp | 559 | 582 | -23 |
| 1980-09-08 | vs CIN | 137 | L 1-6 | 71-66 | 4 | 15,951 | Doyle Alexander | Frank Pastore | Frank Pastore | Doyle Alexander | | 560 | 588 | -28 |
| 1980-09-09 | vs CIN | 138 | L 1-7 | 71-67 | 4 | 14,165 | Tommy Boggs | Mario Soto | Mario Soto | Tommy Boggs | | 561 | 595 | -34 |
| 1980-09-10 | vs CIN | 139 | L 0-3 | 71-68 | 4 | 10,516 | Larry McWilliams | Tom Seaver | Tom Seaver | Larry McWilliams | | 561 | 598 | -37 |
| 1980-09-12 | vs SDN | 140 | W 6-2 | 72-68 | 4 | 8,881 | Phil Niekro | Juan Eichelberger | Phil Niekro | Juan Eichelberger | Rick Camp | 567 | 600 | -33 |
| 1980-09-13 | vs SDN | 141 | W 5-3 | 73-68 | 4 | 12,990 | Rick Matula | Rick Wise | Rick Matula | Rick Wise | Rick Camp | 572 | 603 | -31 |
| 1980-09-14 | vs SDN | 142 | W 4-3 | 74-68 | 4 | 9,270 | Doyle Alexander | Steve Mura | Rick Camp | Gary Lucas | | 576 | 606 | -30 |
| 1980-09-15 | vs LAN | 143 | W 9-0 | 75-68 | 4 | 8,025 | Tommy Boggs | Burt Hooton | Tommy Boggs | Burt Hooton | | 585 | 606 | -21 |
| 1980-09-16 | vs LAN | 144 | W 2-1 | 76-68 | 4 | 31,279 | Phil Niekro | Dave Goltz | Phil Niekro | Dave Goltz | Rick Camp | 587 | 607 | -20 |
| 1980-09-17 | @ SFN | 145 | L 0-2 | 76-69 | 4 | 2,164 | Larry McWilliams | Vida Blue | Vida Blue | Larry McWilliams | | 587 | 609 | -22 |
| 1980-09-18 | @ SFN | 146 | W 2-1 | 77-69 | 4 | 2,151 | Rick Matula | Alan Hargesheimer | Rick Matula | Alan Hargesheimer | Rick Camp | 589 | 610 | -21 |
| 1980-09-19 | @ SDN | 147 | L 4-7 | 77-70 | 4 | 5,893 | Doyle Alexander | Steve Mura | Steve Mura | Doyle Alexander | Rollie Fingers | 593 | 617 | -24 |
| 1980-09-20 | @ SDN | 148 | L 2-3 | 77-71 | 4 | 7,180 | Tommy Boggs | George Stablein | Eric Rasmussen | Al Hrabosky | | 595 | 620 | -25 |
| 1980-09-21 | @ SDN | 149 | L 1-3 | 77-72 | 4 | 2,846 | Phil Niekro | Tom Tellmann | Tom Tellmann | Phil Niekro | | 596 | 623 | -27 |
| 1980-09-22 | @ LAN | 150 | W 7-2 | 78-72 | 4 | 25,078 | Preston Hanna | Don Sutton | Preston Hanna | Don Sutton | Rick Camp | 603 | 625 | -22 |
| 1980-09-23 | @ LAN | 151 | L 2-4 | 78-73 | 4 | 29,226 | Rick Matula | Bob Welch | Bob Welch | Rick Matula | Don Stanhouse | 605 | 629 | -24 |
| 1980-09-24 | vs HOU | 152 | W 4-2 | 79-73 | 4 | 24,897 | Doyle Alexander | Joaquin Andujar | Doyle Alexander | Joaquin Andujar | Rick Camp | 609 | 631 | -22 |
| 1980-09-25 | vs HOU | 153 | L 2-4 | 79-74 | 4 | 7,926 | Phil Niekro | Nolan Ryan | Nolan Ryan | Phil Niekro | Dave Smith | 611 | 635 | -24 |
| 1980-09-26 | vs SFN | 154 | W 5-3 | 80-74 | 4 | 6,578 | Tommy Boggs | Vida Blue | Tommy Boggs | Vida Blue | Rick Camp | 616 | 638 | -22 |
| 1980-09-27 | vs SFN | 155 | L 1-2 | 80-75 | 4 | 19,486 | Larry McWilliams | Allen Ripley | Allen Ripley | Larry McWilliams | Gary Lavelle | 617 | 640 | -23 |
| 1980-09-30 | @ HOU | 156 | L 3-7 | 80-76 | 4 | 31,973 | Doyle Alexander | Nolan Ryan | Nolan Ryan | Doyle Alexander | Dave Smith | 620 | 647 | -27 |
| 1980-10-01 | @ HOU | 157 | L 2-5 | 80-77 | 4 | 35,600 | Phil Niekro | Vern Ruhle | Vern Ruhle | Phil Niekro | | 622 | 652 | -30 |
| 1980-10-02 | @ HOU | 158 | L 2-3 | 80-78 | 4 | 45,022 | Larry McWilliams | Joe Niekro | Joe Niekro | Larry McWilliams | Frank LaCorte | 624 | 655 | -31 |
| 1980-10-03 | @ CIN | 159 | W 4-1 | 81-78 | 4 | 18,868 | Tommy Boggs | Mario Soto | Tommy Boggs | Mario Soto | Rick Camp | 628 | 656 | -28 |
| 1980-10-04 | @ CIN | 160 | L 2-3 | 81-79 | 4 | 14,376 | Doyle Alexander | Frank Pastore | Frank Pastore | Doyle Alexander | | 630 | 659 | -29 |
| 1980-10-05 | @ CIN | 161 | L 0-1 | 81-80 | 4 | 30,478 | Phil Niekro | Joe Price | Joe Price | Phil Niekro | Tom Hume | 630 | 660 | -30 |