| 2003-03-31 | vs MON | 1 | L 2-10 | 0-1 | 3 | 40,258 | Greg Maddux | Tony Armas | Tony Armas | Greg Maddux | | 2 | 10 | -8 |
| 2003-04-02 | vs MON | 2 | L 0-3 | 0-2 | 4 | 19,116 | Horacio Ramirez | Zach Day | Zach Day | Horacio Ramirez | Rocky Biddle | 2 | 13 | -11 |
| 2003-04-03 | vs MON | 3 | L 0-4 | 0-3 | 5 | 19,505 | Russ Ortiz | Javier Vazquez | Javier Vazquez | Russ Ortiz | | 2 | 17 | -15 |
| 2003-04-04 | vs FLO | 4 | W 12-7 | 1-3 | 4 | 20,642 | Jason Marquis | Michael Tejera | Roberto Hernandez | Vladimir Nunez | John Smoltz | 14 | 24 | -10 |
| 2003-04-05 | vs FLO | 5 | L 1-17 | 1-4 | 5 | 23,081 | Greg Maddux | Josh Beckett | Josh Beckett | Greg Maddux | | 15 | 41 | -26 |
| 2003-04-06 | vs FLO | 6 | W 13-4 | 2-4 | 4 | 21,253 | Horacio Ramirez | Brad Penny | Horacio Ramirez | Brad Penny | | 28 | 45 | -17 |
| 2003-04-07 | vs FLO | 7 | W 3-0 | 3-4 | 4 | 19,326 | Russ Ortiz | Carl Pavano | Russ Ortiz | Carl Pavano | John Smoltz | 31 | 45 | -14 |
| 2003-04-08 | @ PHI | 8 | L 3-4 | 3-5 | 4 | 13,283 | Jason Marquis | Randy Wolf | Jose Mesa | Kevin Gryboski | | 34 | 49 | -15 |
| 2003-04-09 | @ PHI | 9 | L 2-16 | 3-6 | 4 | 14,724 | Greg Maddux | Vicente Padilla | Vicente Padilla | Greg Maddux | | 36 | 65 | -29 |
| 2003-04-10 | @ PHI | 10 | W 6-2 | 4-6 | 4 | 14,840 | Trey Hodges | Joe Roa | Darren Holmes | Joe Roa | | 42 | 67 | -25 |
| 2003-04-11 | @ FLO | 11 | L 4-7 | 4-7 | 5 | 12,045 | Horacio Ramirez | Brad Penny | Brad Penny | Horacio Ramirez | Braden Looper | 46 | 74 | -28 |
| 2003-04-12 | @ FLO | 12 | L 5-12 | 4-8 | 5 | 25,203 | Russ Ortiz | Carl Pavano | Carl Pavano | Russ Ortiz | | 51 | 86 | -35 |
| 2003-04-13 | @ FLO | 13 | W 7-1 | 5-8 | 4 | 21,834 | Greg Maddux | Mark Redman | Greg Maddux | Mark Redman | John Smoltz | 58 | 87 | -29 |
| 2003-04-15 | @ MON | 14 | W 2-1 | 6-8 | 3 | 13,399 | Shane Reynolds | Tony Armas | Jung Bong | Dan Smith | John Smoltz | 60 | 88 | -28 |
| 2003-04-16 | @ MON | 15 | W 3-2 | 7-8 | 3 | 15,571 | Horacio Ramirez | Tomo Ohka | Horacio Ramirez | Tomo Ohka | John Smoltz | 63 | 90 | -27 |
| 2003-04-17 | @ MON | 16 | W 14-8 | 8-8 | 3 | 13,170 | Russ Ortiz | Livan Hernandez | Jung Bong | Rocky Biddle | | 77 | 98 | -21 |
| 2003-04-18 | vs PHI | 17 | W 5-4 | 9-8 | 2 | 28,100 | Greg Maddux | Randy Wolf | Kevin Gryboski | Randy Wolf | John Smoltz | 82 | 102 | -20 |
| 2003-04-19 | vs PHI | 18 | L 0-4 | 9-9 | 3 | 29,777 | Mike Hampton | Vicente Padilla | Vicente Padilla | Mike Hampton | | 82 | 106 | -24 |
| 2003-04-20 | vs PHI | 19 | W 8-1 | 10-9 | 2 | 22,978 | Shane Reynolds | Brandon Duckworth | Shane Reynolds | Brandon Duckworth | | 90 | 107 | -17 |
| 2003-04-22 | vs SLN | 20 | W 5-3 | 11-9 | 2 | 20,969 | Russ Ortiz | Garrett Stephenson | Russ Ortiz | Garrett Stephenson | John Smoltz | 95 | 110 | -15 |
| 2003-04-23 | vs SLN | 21 | W 4-2 | 12-9 | 1 | 21,338 | Greg Maddux | Matt Morris | Greg Maddux | Matt Morris | John Smoltz | 99 | 112 | -13 |
| 2003-04-24 | vs SLN | 22 | W 4-3 | 13-9 | 1 | 24,184 | Mike Hampton | Woody Williams | Ray King | Steve Kline | | 103 | 115 | -12 |
| 2003-04-25 | vs MIL | 23 | L 5-12 | 13-10 | 2 | 21,938 | Shane Reynolds | Ben Sheets | Ben Sheets | Shane Reynolds | | 108 | 127 | -19 |
| 2003-04-26 | vs MIL | 24 | W 3-2 | 14-10 | 2 | 27,313 | Horacio Ramirez | Wayne Franklin | Ray King | Valerio de los Santos | John Smoltz | 111 | 129 | -18 |
| 2003-04-27 | vs MIL | 25 | W 7-1 | 15-10 | 1 | 26,349 | Russ Ortiz | Glendon Rusch | Russ Ortiz | Glendon Rusch | | 118 | 130 | -12 |
| 2003-04-29 | @ HOU | 26 | W 3-1 | 16-10 | 1 | 28,467 | Greg Maddux | Roy Oswalt | Greg Maddux | Roy Oswalt | John Smoltz | 121 | 131 | -10 |
| 2003-04-30 | @ HOU | 27 | W 11-1 | 17-10 | 1 | 24,018 | Mike Hampton | Wade Miller | Mike Hampton | Wade Miller | | 132 | 132 | 0 |
| 2003-05-01 | @ HOU | 28 | W 8-7 | 18-10 | 1 | 24,673 | Shane Reynolds | Jeriome Robertson | Roberto Hernandez | Billy Wagner | John Smoltz | 140 | 139 | 1 |
| 2003-05-02 | @ ARI | 29 | W 4-2 | 19-10 | 1 | 38,287 | Horacio Ramirez | Brandon Webb | Jung Bong | Matt Mantei | | 144 | 141 | 3 |
| 2003-05-03 | @ ARI | 30 | L 6-7 | 19-11 | 1 | 44,398 | Russ Ortiz | Curt Schilling | Oscar Villarreal | Kevin Gryboski | Matt Mantei | 150 | 148 | 2 |
| 2003-05-04 | @ ARI | 31 | W 7-4 | 20-11 | 1 | 38,851 | Greg Maddux | Elmer Dessens | Trey Hodges | Chris Capuano | John Smoltz | 157 | 152 | 5 |
| 2003-05-06 | vs COL | 32 | W 3-2 | 21-11 | 1 | 18,108 | Mike Hampton | Aaron Cook | Roberto Hernandez | Todd Jones | John Smoltz | 160 | 154 | 6 |
| 2003-05-08 | vs COL | 33 | W 12-6 | 23-11 | 1 | 0 | Shane Reynolds | Nelson Cruz | Shane Reynolds | Nelson Cruz | John Smoltz | 172 | 160 | 12 |
| 2003-05-08 | vs COL | 34 | W 5-2 | 23-11 | 1 | 22,829 | Russ Ortiz | Shawn Chacon | Russ Ortiz | Shawn Chacon | John Smoltz | 177 | 162 | 15 |
| 2003-05-09 | vs SFN | 35 | L 2-9 | 23-12 | 1 | 32,040 | Greg Maddux | Jesse Foppert | Jesse Foppert | Greg Maddux | Jim Brower | 179 | 171 | 8 |
| 2003-05-10 | vs SFN | 36 | W 6-3 | 24-12 | 1 | 39,357 | Horacio Ramirez | Kirk Rueter | Kevin Gryboski | Joe Nathan | | 185 | 174 | 11 |
| 2003-05-11 | vs SFN | 37 | W 7-3 | 25-12 | 1 | 28,329 | Mike Hampton | Jason Schmidt | Mike Hampton | Jason Schmidt | | 192 | 177 | 15 |
| 2003-05-12 | @ LAN | 38 | W 11-4 | 26-12 | 1 | 27,458 | Shane Reynolds | Hideo Nomo | Jung Bong | Eric Gagne | | 203 | 181 | 22 |
| 2003-05-13 | @ LAN | 39 | W 3-1 | 27-12 | 1 | 31,021 | Russ Ortiz | Kazuhisa Ishii | Russ Ortiz | Paul Quantrill | John Smoltz | 206 | 182 | 24 |
| 2003-05-14 | @ LAN | 40 | L 1-5 | 27-13 | 1 | 29,343 | Greg Maddux | Kevin Brown | Kevin Brown | Greg Maddux | | 207 | 187 | 20 |
| 2003-05-15 | @ SDN | 41 | W 15-6 | 28-13 | 1 | 15,818 | Horacio Ramirez | Roger Deago | Horacio Ramirez | Roger Deago | | 222 | 193 | 29 |
| 2003-05-16 | @ SDN | 42 | W 6-4 | 29-13 | 1 | 24,229 | Mike Hampton | Jake Peavy | Kevin Gryboski | Charles Nagy | John Smoltz | 228 | 197 | 31 |
| 2003-05-17 | @ SDN | 43 | W 12-2 | 30-13 | 1 | 28,551 | Shane Reynolds | Carlton Loewer | Shane Reynolds | Carlton Loewer | | 240 | 199 | 41 |
| 2003-05-18 | @ SDN | 44 | W 6-3 | 31-13 | 1 | 23,776 | Russ Ortiz | Brian Lawrence | Russ Ortiz | Brian Lawrence | John Smoltz | 246 | 202 | 44 |
| 2003-05-20 | @ CIN | 45 | L 8-9 | 31-14 | 1 | 24,076 | Greg Maddux | Danny Graves | Scott Sullivan | Roberto Hernandez | Scott Williamson | 254 | 211 | 43 |
| 2003-05-21 | @ CIN | 46 | L 3-9 | 31-15 | 1 | 33,355 | Mike Hampton | John Riedling | Chris Reitsma | Mike Hampton | | 257 | 220 | 37 |
| 2003-05-22 | @ CIN | 47 | W 9-4 | 32-15 | 1 | 28,962 | Shane Reynolds | Ryan Dempster | Shane Reynolds | Ryan Dempster | | 266 | 224 | 42 |
| 2003-05-23 | vs NYN | 48 | L 5-6 | 32-16 | 1 | 33,270 | Russ Ortiz | Steve Trachsel | Steve Trachsel | Russ Ortiz | Armando Benitez | 271 | 230 | 41 |
| 2003-05-24 | vs NYN | 49 | W 10-4 | 33-16 | 1 | 40,912 | Horacio Ramirez | Tom Glavine | Horacio Ramirez | Tom Glavine | | 281 | 234 | 47 |
| 2003-05-25 | vs NYN | 50 | W 3-1 | 34-16 | 1 | 41,432 | Greg Maddux | Jae Weong Seo | Roberto Hernandez | David Weathers | John Smoltz | 284 | 235 | 49 |
| 2003-05-26 | vs CIN | 51 | L 6-7 | 34-17 | 1 | 33,455 | Mike Hampton | John Riedling | Gabe White | Roberto Hernandez | | 290 | 242 | 48 |
| 2003-05-27 | vs CIN | 52 | W 3-2 | 35-17 | 1 | 23,041 | Shane Reynolds | Jimmy Haynes | Trey Hodges | Chris Reitsma | | 293 | 244 | 49 |
| 2003-05-28 | vs CIN | 53 | W 15-3 | 36-17 | 1 | 25,713 | Russ Ortiz | Jeff Austin | Russ Ortiz | Jeff Austin | Jung Bong | 308 | 247 | 61 |
| 2003-05-30 | @ NYN | 54 | W 5-2 | 37-17 | 1 | 26,439 | Greg Maddux | Tom Glavine | Greg Maddux | Tom Glavine | John Smoltz | 313 | 249 | 64 |
| 2003-05-31 | @ NYN | 55 | L 2-4 | 37-18 | 1 | 33,378 | Mike Hampton | Jae Weong Seo | Jae Weong Seo | Mike Hampton | Armando Benitez | 315 | 253 | 62 |
| 2003-06-01 | @ NYN | 56 | L 4-10 | 37-19 | 1 | 25,162 | Horacio Ramirez | Al Leiter | Al Leiter | Kevin Gryboski | | 319 | 263 | 56 |
| 2003-06-03 | vs TEX | 57 | W 6-5 | 38-19 | 1 | 30,444 | Russ Ortiz | Ismael Valdez | Kevin Gryboski | Ugueth Urbina | John Smoltz | 325 | 268 | 57 |
| 2003-06-04 | vs TEX | 58 | W 5-2 | 39-19 | 1 | 30,836 | Greg Maddux | John Thomson | Greg Maddux | John Thomson | John Smoltz | 330 | 270 | 60 |
| 2003-06-05 | vs TEX | 59 | W 8-4 | 40-19 | 1 | 35,944 | Mike Hampton | Victor Santos | Jung Bong | Aaron Fultz | | 338 | 274 | 64 |
| 2003-06-07 | vs PIT | 60 | W 8-6 | 41-19 | 1 | 35,397 | Shane Reynolds | Kip Wells | Roberto Hernandez | Brian Boehringer | John Smoltz | 346 | 280 | 66 |
| 2003-06-08 | vs PIT | 61 | W 6-5 | 42-19 | 1 | 29,869 | Russ Ortiz | Josh Fogg | Trey Hodges | Josh Fogg | John Smoltz | 352 | 285 | 67 |
| 2003-06-10 | @ OAK | 62 | L 3-4 | 42-20 | 1 | 22,088 | Greg Maddux | Tim Hudson | Chad Bradford | Jung Bong | | 355 | 289 | 66 |
| 2003-06-11 | @ OAK | 63 | W 11-6 | 43-20 | 1 | 35,618 | Horacio Ramirez | Ted Lilly | Horacio Ramirez | Ted Lilly | | 366 | 295 | 71 |
| 2003-06-12 | @ OAK | 64 | W 4-2 | 44-20 | 1 | 21,173 | Shane Reynolds | Barry Zito | Shane Reynolds | Barry Zito | John Smoltz | 370 | 297 | 73 |
| 2003-06-13 | @ SEA | 65 | L 1-2 | 44-21 | 1 | 45,791 | Russ Ortiz | Freddy Garcia | Freddy Garcia | Russ Ortiz | Jeff Nelson | 371 | 299 | 72 |
| 2003-06-14 | @ SEA | 66 | W 3-1 | 45-21 | 1 | 45,971 | Mike Hampton | Jamie Moyer | Mike Hampton | Jamie Moyer | John Smoltz | 374 | 300 | 74 |
| 2003-06-15 | @ SEA | 67 | L 1-2 | 45-22 | 1 | 45,732 | Greg Maddux | Gil Meche | Gil Meche | Greg Maddux | Jeff Nelson | 375 | 302 | 73 |
| 2003-06-17 | @ PHI | 68 | L 4-5 | 45-23 | 1 | 24,133 | Shane Reynolds | Brett Myers | Turk Wendell | Darren Holmes | | 379 | 307 | 72 |
| 2003-06-18 | @ PHI | 69 | W 6-1 | 46-23 | 1 | 26,475 | Russ Ortiz | Kevin Millwood | Russ Ortiz | Kevin Millwood | | 385 | 308 | 77 |
| 2003-06-19 | @ PHI | 70 | L 2-3 | 46-24 | 1 | 27,207 | Mike Hampton | Vicente Padilla | Jose Mesa | John Smoltz | | 387 | 311 | 76 |
| 2003-06-20 | vs BAL | 71 | W 6-3 | 47-24 | 1 | 35,526 | Greg Maddux | Sidney Ponson | Greg Maddux | Sidney Ponson | John Smoltz | 393 | 314 | 79 |
| 2003-06-21 | vs BAL | 72 | W 10-2 | 48-24 | 1 | 46,860 | Horacio Ramirez | Rodrigo Lopez | Horacio Ramirez | Rodrigo Lopez | | 403 | 316 | 87 |
| 2003-06-22 | vs BAL | 73 | L 3-9 | 48-25 | 1 | 34,904 | Shane Reynolds | Jason Johnson | Jason Johnson | Shane Reynolds | Pat Hentgen | 406 | 325 | 81 |
| 2003-06-24 | vs PHI | 74 | W 5-3 | 49-25 | 1 | 31,796 | Russ Ortiz | Kevin Millwood | Russ Ortiz | Kevin Millwood | John Smoltz | 411 | 328 | 83 |
| 2003-06-25 | vs PHI | 75 | L 1-8 | 49-26 | 1 | 31,724 | Greg Maddux | Vicente Padilla | Vicente Padilla | Greg Maddux | | 412 | 336 | 76 |
| 2003-06-26 | vs PHI | 76 | L 1-8 | 49-27 | 1 | 30,405 | Mike Hampton | Randy Wolf | Randy Wolf | Mike Hampton | | 413 | 344 | 69 |
| 2003-06-27 | @ TBA | 77 | W 8-2 | 50-27 | 1 | 16,398 | Horacio Ramirez | Geremi Gonzalez | Horacio Ramirez | Geremi Gonzalez | | 421 | 346 | 75 |
| 2003-06-28 | @ TBA | 78 | L 7-9 | 50-28 | 1 | 26,696 | Shane Reynolds | Victor Zambrano | Victor Zambrano | Shane Reynolds | Lance Carter | 428 | 355 | 73 |
| 2003-06-29 | @ TBA | 79 | W 2-0 | 51-28 | 1 | 22,670 | Russ Ortiz | Jorge Sosa | Russ Ortiz | Jorge Sosa | John Smoltz | 430 | 355 | 75 |
| 2003-06-30 | @ FLO | 80 | L 1-8 | 51-29 | 1 | 11,254 | Greg Maddux | Mark Redman | Mark Redman | Greg Maddux | | 431 | 363 | 68 |
| 2003-07-01 | @ FLO | 81 | L 1-20 | 51-30 | 1 | 13,073 | Mike Hampton | Josh Beckett | Josh Beckett | Mike Hampton | | 432 | 383 | 49 |
| 2003-07-02 | @ FLO | 82 | W 2-1 | 52-30 | 1 | 30,634 | Horacio Ramirez | Dontrelle Willis | Kevin Gryboski | Armando Almanza | John Smoltz | 434 | 384 | 50 |
| 2003-07-03 | vs MON | 83 | L 4-5 | 52-31 | 1 | 31,607 | Shane Reynolds | Claudio Vargas | Claudio Vargas | Shane Reynolds | Julio Manon | 438 | 389 | 49 |
| 2003-07-04 | vs MON | 84 | W 8-6 | 53-31 | 1 | 48,923 | Russ Ortiz | Tomo Ohka | Russ Ortiz | Tomo Ohka | John Smoltz | 446 | 395 | 51 |
| 2003-07-05 | vs MON | 85 | W 3-2 | 54-31 | 1 | 34,454 | Greg Maddux | Javier Vazquez | Jung Bong | Rocky Biddle | | 449 | 397 | 52 |
| 2003-07-06 | vs MON | 86 | W 7-5 | 55-31 | 1 | 27,724 | Mike Hampton | Tim Drew | Mike Hampton | Tim Drew | John Smoltz | 456 | 402 | 54 |
| 2003-07-07 | @ NYN | 87 | W 7-3 | 56-31 | 1 | 32,399 | Horacio Ramirez | Jae Weong Seo | Horacio Ramirez | Jae Weong Seo | | 463 | 405 | 58 |
| 2003-07-08 | @ NYN | 88 | W 5-3 | 57-31 | 1 | 29,096 | Shane Reynolds | Jason Roach | Shane Reynolds | Jason Roach | John Smoltz | 468 | 408 | 60 |
| 2003-07-09 | @ NYN | 89 | W 6-3 | 58-31 | 1 | 30,308 | Russ Ortiz | Tom Glavine | Russ Ortiz | Tom Glavine | John Smoltz | 474 | 411 | 63 |
| 2003-07-10 | @ CHN | 90 | W 13-3 | 59-31 | 1 | 38,756 | Greg Maddux | Shawn Estes | Greg Maddux | Shawn Estes | | 487 | 414 | 73 |
| 2003-07-11 | @ CHN | 91 | W 9-5 | 60-31 | 1 | 39,334 | Mike Hampton | Mark Prior | Mike Hampton | Mark Prior | | 496 | 419 | 77 |
| 2003-07-12 | @ CHN | 92 | L 3-7 | 60-32 | 1 | 39,980 | Horacio Ramirez | Matt Clement | Matt Clement | Horacio Ramirez | | 499 | 426 | 73 |
| 2003-07-13 | @ CHN | 93 | W 7-2 | 61-32 | 1 | 39,832 | Shane Reynolds | Carlos Zambrano | Shane Reynolds | Carlos Zambrano | | 506 | 428 | 78 |
| 2003-07-17 | vs NYN | 94 | W 3-2 | 62-32 | 1 | 36,688 | Greg Maddux | Steve Trachsel | Greg Maddux | John Franco | | 509 | 430 | 79 |
| 2003-07-18 | vs NYN | 95 | W 11-4 | 63-32 | 1 | 44,815 | Mike Hampton | Jae Weong Seo | Mike Hampton | Jae Weong Seo | | 520 | 434 | 86 |
| 2003-07-19 | vs NYN | 96 | W 7-4 | 64-32 | 1 | 45,759 | Russ Ortiz | Tom Glavine | Russ Ortiz | Tom Glavine | John Smoltz | 527 | 438 | 89 |
| 2003-07-20 | vs NYN | 97 | W 11-8 | 65-32 | 1 | 36,029 | Horacio Ramirez | Al Leiter | Ray King | Mike Stanton | John Smoltz | 538 | 446 | 92 |
| 2003-07-21 | vs CHN | 98 | L 6-15 | 65-33 | 1 | 39,950 | Shane Reynolds | Shawn Estes | Dave Veres | Shane Reynolds | | 544 | 461 | 83 |
| 2003-07-22 | vs CHN | 99 | W 8-4 | 66-33 | 1 | 39,226 | Greg Maddux | Sergio Mitre | Greg Maddux | Sergio Mitre | | 552 | 465 | 87 |
| 2003-07-23 | vs FLO | 100 | L 4-5 | 66-34 | 1 | 27,137 | Mike Hampton | Mark Redman | Nate Bump | Trey Hodges | | 556 | 470 | 86 |
| 2003-07-24 | vs FLO | 101 | W 5-2 | 67-34 | 1 | 33,711 | Russ Ortiz | Brad Penny | Russ Ortiz | Brad Penny | John Smoltz | 561 | 472 | 89 |
| 2003-07-25 | @ MON | 102 | L 8-9 | 67-35 | 1 | 10,069 | Horacio Ramirez | Claudio Vargas | Luis Ayala | Jung Bong | | 569 | 481 | 88 |
| 2003-07-26 | @ MON | 103 | W 15-4 | 68-35 | 1 | 14,132 | Shane Reynolds | Zach Day | Shane Reynolds | Zach Day | | 584 | 485 | 99 |
| 2003-07-27 | @ MON | 104 | L 10-13 | 68-36 | 1 | 16,074 | Greg Maddux | Tomo Ohka | Julio Manon | Ray King | Rocky Biddle | 594 | 498 | 96 |
| 2003-07-28 | @ MON | 105 | W 10-8 | 69-36 | 1 | 9,750 | Mike Hampton | Javier Vazquez | Mike Hampton | Javier Vazquez | John Smoltz | 604 | 506 | 98 |
| 2003-07-29 | vs HOU | 106 | W 6-3 | 70-36 | 1 | 30,415 | Russ Ortiz | Roy Oswalt | Russ Ortiz | Ricky Stone | John Smoltz | 610 | 509 | 101 |
| 2003-07-30 | vs HOU | 107 | L 3-7 | 70-37 | 1 | 27,960 | Horacio Ramirez | Ron Villone | Ron Villone | Horacio Ramirez | | 613 | 516 | 97 |
| 2003-07-31 | vs HOU | 108 | W 7-4 | 71-37 | 1 | 30,047 | Shane Reynolds | Wade Miller | Shane Reynolds | Wade Miller | John Smoltz | 620 | 520 | 100 |
| 2003-08-01 | vs LAN | 109 | W 2-0 | 72-37 | 1 | 37,951 | Greg Maddux | Hideo Nomo | Greg Maddux | Hideo Nomo | John Smoltz | 622 | 520 | 102 |
| 2003-08-02 | vs LAN | 110 | W 6-4 | 73-37 | 1 | 47,506 | Mike Hampton | Andy Ashby | Mike Hampton | Andy Ashby | John Smoltz | 628 | 524 | 104 |
| 2003-08-03 | vs LAN | 111 | L 4-8 | 73-38 | 1 | 34,930 | Russ Ortiz | Scott Mullen | Guillermo Mota | Russ Ortiz | | 632 | 532 | 100 |
| 2003-08-05 | @ MIL | 112 | L 3-4 | 73-39 | 1 | 20,986 | Horacio Ramirez | Matt Kinney | Mike DeJean | Darren Holmes | Danny Kolb | 635 | 536 | 99 |
| 2003-08-06 | @ MIL | 113 | W 10-2 | 74-39 | 1 | 30,010 | Greg Maddux | Wayne Franklin | Greg Maddux | Wayne Franklin | | 645 | 538 | 107 |
| 2003-08-07 | @ MIL | 114 | W 7-1 | 75-39 | 1 | 31,097 | Mike Hampton | Wes Obermueller | Mike Hampton | Wes Obermueller | | 652 | 539 | 113 |
| 2003-08-08 | @ SLN | 115 | W 7-2 | 76-39 | 1 | 45,796 | Russ Ortiz | Jeff Fassero | Russ Ortiz | Jeff Fassero | | 659 | 541 | 118 |
| 2003-08-09 | @ SLN | 116 | L 1-3 | 76-40 | 1 | 47,692 | Shane Reynolds | Garrett Stephenson | Garrett Stephenson | Shane Reynolds | Jason Isringhausen | 660 | 544 | 116 |
| 2003-08-10 | @ SLN | 117 | L 2-3 | 76-41 | 1 | 39,320 | Horacio Ramirez | Woody Williams | Cal Eldred | John Smoltz | Jason Isringhausen | 662 | 547 | 115 |
| 2003-08-12 | vs SDN | 118 | L 4-14 | 76-42 | 1 | 25,422 | Greg Maddux | Adam Eaton | Adam Eaton | Greg Maddux | | 666 | 561 | 105 |
| 2003-08-13 | vs SDN | 119 | W 7-1 | 77-42 | 1 | 20,862 | Mike Hampton | Kevin Jarvis | Mike Hampton | Kevin Jarvis | | 673 | 562 | 111 |
| 2003-08-14 | vs SDN | 120 | W 7-4 | 78-42 | 1 | 23,923 | Russ Ortiz | Jake Peavy | Russ Ortiz | Jake Peavy | John Smoltz | 680 | 566 | 114 |
| 2003-08-15 | vs ARI | 121 | W 10-4 | 79-42 | 1 | 34,544 | Shane Reynolds | Randy Johnson | Shane Reynolds | Randy Johnson | | 690 | 570 | 120 |
| 2003-08-16 | vs ARI | 122 | W 10-6 | 80-42 | 1 | 49,127 | Horacio Ramirez | Elmer Dessens | Kevin Gryboski | Eddie Oropesa | | 700 | 576 | 124 |
| 2003-08-17 | vs ARI | 123 | L 0-2 | 80-43 | 1 | 37,606 | Greg Maddux | Curt Schilling | Curt Schilling | Greg Maddux | Matt Mantei | 700 | 578 | 122 |
| 2003-08-18 | vs ARI | 124 | W 6-1 | 81-43 | 1 | 23,986 | Mike Hampton | Miguel Batista | Mike Hampton | Miguel Batista | | 706 | 579 | 127 |
| 2003-08-19 | @ SFN | 125 | L 4-5 | 81-44 | 1 | 42,307 | Russ Ortiz | Jerome Williams | Tim Worrell | Ray King | | 710 | 584 | 126 |
| 2003-08-20 | @ SFN | 126 | L 1-2 | 81-45 | 1 | 41,974 | Shane Reynolds | Jesse Foppert | Joe Nathan | Kevin Gryboski | | 711 | 586 | 125 |
| 2003-08-21 | @ SFN | 127 | L 3-4 | 81-46 | 1 | 41,745 | Horacio Ramirez | Jason Schmidt | Felix Rodriguez | Trey Hodges | | 714 | 590 | 124 |
| 2003-08-22 | @ COL | 128 | W 9-3 | 82-46 | 1 | 35,578 | Greg Maddux | Jason Jennings | Greg Maddux | Jason Jennings | | 723 | 593 | 130 |
| 2003-08-23 | @ COL | 129 | W 5-4 | 83-46 | 1 | 42,303 | Mike Hampton | Chin-hui Tsao | Mike Hampton | Chin-hui Tsao | John Smoltz | 728 | 597 | 131 |
| 2003-08-24 | @ COL | 130 | W 12-6 | 84-46 | 1 | 31,227 | Russ Ortiz | Denny Stark | Russ Ortiz | Denny Stark | | 740 | 603 | 137 |
| 2003-08-26 | vs NYN | 131 | L 5-6 | 84-47 | 1 | 24,694 | Shane Reynolds | Jae Weong Seo | Jae Weong Seo | Shane Reynolds | Mike Stanton | 745 | 609 | 136 |
| 2003-08-27 | vs NYN | 132 | W 4-1 | 85-47 | 1 | 23,755 | Greg Maddux | Aaron Heilman | Greg Maddux | Aaron Heilman | Kent Mercker | 749 | 610 | 139 |
| 2003-08-28 | vs NYN | 133 | L 1-3 | 85-48 | 1 | 27,856 | Mike Hampton | Al Leiter | Al Leiter | Mike Hampton | David Weathers | 750 | 613 | 137 |
| 2003-08-29 | @ PIT | 134 | L 5-6 | 85-49 | 1 | 27,415 | Russ Ortiz | Salomon Torres | Julian Tavarez | Will Cunnane | | 755 | 619 | 136 |
| 2003-08-30 | @ PIT | 135 | W 13-6 | 86-49 | 1 | 21,323 | Horacio Ramirez | Oliver Perez | Horacio Ramirez | Oliver Perez | | 768 | 625 | 143 |
| 2003-08-31 | @ PIT | 136 | W 10-4 | 87-49 | 1 | 23,822 | Shane Reynolds | Jeff D'Amico | Shane Reynolds | Jeff D'Amico | | 778 | 629 | 149 |
| 2003-09-01 | @ NYN | 137 | L 2-3 | 87-50 | 1 | 23,877 | Greg Maddux | Jeremy Griffiths | Dan Wheeler | Trey Hodges | David Weathers | 780 | 632 | 148 |
| 2003-09-02 | @ NYN | 138 | L 1-3 | 87-51 | 1 | 24,390 | Mike Hampton | Al Leiter | Al Leiter | Mike Hampton | David Weathers | 781 | 635 | 146 |
| 2003-09-03 | @ NYN | 139 | L 3-9 | 87-52 | 1 | 16,439 | Russ Ortiz | Steve Trachsel | Steve Trachsel | Russ Ortiz | | 784 | 644 | 140 |
| 2003-09-05 | vs PIT | 140 | W 3-2 | 88-53 | 1 | 0 | Horacio Ramirez | Oliver Perez | Will Cunnane | Mark Corey | | 787 | 646 | 141 |
| 2003-09-05 | vs PIT | 141 | L 3-5 | 88-53 | 1 | 31,849 | Shane Reynolds | Brian Meadows | Mark Corey | Shane Reynolds | Julian Tavarez | 790 | 651 | 139 |
| 2003-09-06 | vs PIT | 142 | W 9-2 | 89-53 | 1 | 36,932 | Greg Maddux | Jeff D'Amico | Greg Maddux | Jeff D'Amico | | 799 | 653 | 146 |
| 2003-09-07 | vs PIT | 143 | W 2-1 | 90-53 | 1 | 27,703 | Mike Hampton | Kip Wells | Mike Hampton | Kip Wells | Will Cunnane | 801 | 654 | 147 |
| 2003-09-08 | vs PHI | 144 | W 6-4 | 91-53 | 1 | 17,543 | Russ Ortiz | Kevin Millwood | Russ Ortiz | Kevin Millwood | Will Cunnane | 807 | 658 | 149 |
| 2003-09-09 | vs PHI | 145 | L 5-18 | 91-54 | 1 | 21,257 | Shane Reynolds | Randy Wolf | Randy Wolf | Shane Reynolds | | 812 | 676 | 136 |
| 2003-09-10 | vs PHI | 146 | W 4-2 | 92-54 | 1 | 21,321 | Horacio Ramirez | Vicente Padilla | Horacio Ramirez | Vicente Padilla | Will Cunnane | 816 | 678 | 138 |
| 2003-09-11 | vs PHI | 147 | L 3-8 | 92-55 | 1 | 23,811 | Greg Maddux | Brett Myers | Brett Myers | Greg Maddux | | 819 | 686 | 133 |
| 2003-09-12 | @ FLO | 148 | L 4-5 | 92-56 | 1 | 25,622 | Mike Hampton | Brad Penny | Braden Looper | Ray King | | 823 | 691 | 132 |
| 2003-09-13 | @ FLO | 149 | L 3-8 | 92-57 | 1 | 40,414 | Russ Ortiz | Dontrelle Willis | Dontrelle Willis | Russ Ortiz | | 826 | 699 | 127 |
| 2003-09-14 | @ FLO | 150 | W 8-4 | 93-57 | 1 | 18,725 | Shane Reynolds | Josh Beckett | Will Cunnane | Braden Looper | | 834 | 703 | 131 |
| 2003-09-15 | @ MON | 151 | W 10-6 | 94-57 | 1 | 9,696 | Horacio Ramirez | Livan Hernandez | Horacio Ramirez | Livan Hernandez | | 844 | 709 | 135 |
| 2003-09-16 | @ MON | 152 | L 4-5 | 94-58 | 1 | 9,843 | Greg Maddux | Tomo Ohka | Rocky Biddle | Roberto Hernandez | | 848 | 714 | 134 |
| 2003-09-17 | @ MON | 153 | W 14-4 | 95-58 | 1 | 17,526 | Mike Hampton | T.J. Tucker | Mike Hampton | T.J. Tucker | | 862 | 718 | 144 |
| 2003-09-19 | vs FLO | 154 | W 1-0 | 96-58 | 1 | 35,942 | Russ Ortiz | Josh Beckett | Russ Ortiz | Josh Beckett | | 863 | 718 | 145 |
| 2003-09-20 | vs FLO | 155 | L 5-6 | 96-59 | 1 | 42,496 | Horacio Ramirez | Brad Penny | Rick Helling | Will Cunnane | | 868 | 724 | 144 |
| 2003-09-21 | vs FLO | 156 | W 8-0 | 97-59 | 1 | 33,827 | Greg Maddux | Carl Pavano | Greg Maddux | Carl Pavano | | 876 | 724 | 152 |
| 2003-09-22 | vs FLO | 157 | L 3-6 | 97-60 | 1 | 17,345 | Mike Hampton | Mark Redman | Mark Redman | Mike Hampton | Ugueth Urbina | 879 | 730 | 149 |
| 2003-09-23 | vs MON | 158 | W 2-0 | 98-60 | 1 | 22,539 | Shane Reynolds | Javier Vazquez | Jaret Wright | Javier Vazquez | John Smoltz | 881 | 730 | 151 |
| 2003-09-24 | vs MON | 159 | W 9-1 | 99-60 | 1 | 23,594 | Russ Ortiz | Zach Day | Russ Ortiz | Zach Day | | 890 | 731 | 159 |
| 2003-09-26 | @ PHI | 160 | W 6-0 | 100-60 | 1 | 58,096 | Horacio Ramirez | Vicente Padilla | Horacio Ramirez | Vicente Padilla | | 896 | 731 | 165 |
| 2003-09-27 | @ PHI | 161 | L 6-7 | 100-61 | 1 | 58,303 | Mike Hampton | Amaury Telemaco | Rheal Cormier | Ray King | | 902 | 738 | 164 |
| 2003-09-28 | @ PHI | 162 | W 5-2 | 101-61 | 1 | 58,554 | Greg Maddux | Kevin Millwood | Greg Maddux | Kevin Millwood | Jason Marquis | 907 | 740 | 167 |