| 2003-04-01 | @ OAK | 1 | L 0-5 | 0-1 | 4 | 41,723 | Freddy Garcia | Tim Hudson | Tim Hudson | Freddy Garcia | | 0 | 5 | -5 |
| 2003-04-02 | @ OAK | 2 | L 3-8 | 0-2 | 4 | 17,033 | Jamie Moyer | Barry Zito | Barry Zito | Jamie Moyer | | 3 | 13 | -10 |
| 2003-04-03 | @ OAK | 3 | W 7-6 | 1-2 | 3 | 6,295 | Joel Pineiro | Mark Mulder | Jeff Nelson | Ricardo Rincon | | 10 | 19 | -9 |
| 2003-04-04 | @ TEX | 4 | W 6-4 | 2-2 | 3 | 49,231 | Ryan Franklin | Ismael Valdez | Ryan Franklin | Francisco Cordero | Kazuhiro Sasaki | 16 | 23 | -7 |
| 2003-04-05 | @ TEX | 5 | L 4-8 | 2-3 | 3 | 25,562 | Gil Meche | Colby Lewis | Colby Lewis | Gil Meche | Ugueth Urbina | 20 | 31 | -11 |
| 2003-04-06 | @ TEX | 6 | W 11-2 | 3-3 | 2 | 26,336 | Freddy Garcia | Chan Ho Park | Freddy Garcia | Chan Ho Park | | 31 | 33 | -2 |
| 2003-04-08 | vs ANA | 7 | W 5-0 | 4-3 | 2 | 45,931 | Jamie Moyer | Ramon Ortiz | Jamie Moyer | Ramon Ortiz | | 36 | 33 | 3 |
| 2003-04-09 | vs ANA | 8 | L 1-5 | 4-4 | 2 | 35,492 | Joel Pineiro | Kevin Appier | Kevin Appier | Joel Pineiro | | 37 | 38 | -1 |
| 2003-04-10 | vs ANA | 9 | L 0-3 | 4-5 | 3 | 32,746 | Ryan Franklin | Jarrod Washburn | Jarrod Washburn | Ryan Franklin | Troy Percival | 37 | 41 | -4 |
| 2003-04-11 | vs TEX | 10 | L 2-4 | 4-6 | 3 | 37,784 | Freddy Garcia | Chan Ho Park | Chan Ho Park | Freddy Garcia | Ugueth Urbina | 39 | 45 | -6 |
| 2003-04-12 | vs TEX | 11 | W 13-4 | 5-6 | 3 | 36,591 | Gil Meche | Ryan Drese | Gil Meche | Ryan Drese | | 52 | 49 | 3 |
| 2003-04-13 | vs TEX | 12 | W 4-3 | 6-6 | 3 | 35,496 | Jamie Moyer | John Thomson | Kazuhiro Sasaki | R.A. Dickey | | 56 | 52 | 4 |
| 2003-04-14 | vs OAK | 13 | W 4-3 | 7-6 | 3 | 26,567 | Joel Pineiro | Mark Mulder | Joel Pineiro | Mark Mulder | Kazuhiro Sasaki | 60 | 55 | 5 |
| 2003-04-15 | vs OAK | 14 | W 5-3 | 8-6 | 1 | 26,666 | Ryan Franklin | Ted Lilly | Arthur Rhodes | Micah Bowie | Kazuhiro Sasaki | 65 | 58 | 7 |
| 2003-04-16 | vs OAK | 15 | L 1-4 | 8-7 | 3 | 29,674 | Freddy Garcia | Tim Hudson | Tim Hudson | Freddy Garcia | Keith Foulke | 66 | 62 | 4 |
| 2003-04-17 | vs OAK | 16 | W 4-3 | 9-7 | 1 | 33,412 | Gil Meche | John Halama | Jeff Nelson | Jeremy Fikac | | 70 | 65 | 5 |
| 2003-04-18 | @ ANA | 17 | W 8-2 | 10-7 | 1 | 34,658 | Jamie Moyer | Ramon Ortiz | Jamie Moyer | Ramon Ortiz | | 78 | 67 | 11 |
| 2003-04-19 | @ ANA | 18 | L 6-7 | 10-8 | 2 | 43,536 | Joel Pineiro | Kevin Appier | Francisco Rodriguez | Kazuhiro Sasaki | | 84 | 74 | 10 |
| 2003-04-20 | @ ANA | 19 | W 7-6 | 11-8 | 1 | 28,942 | Ryan Franklin | Jarrod Washburn | Shigetoshi Hasegawa | Troy Percival | Kazuhiro Sasaki | 91 | 80 | 11 |
| 2003-04-22 | vs CLE | 20 | W 8-5 | 12-8 | 1 | 25,231 | Freddy Garcia | CC Sabathia | Giovanni Carrara | Danys Baez | | 99 | 85 | 14 |
| 2003-04-23 | vs CLE | 21 | W 4-0 | 13-8 | 1 | 26,036 | Gil Meche | Ricardo Rodriguez | Gil Meche | Ricardo Rodriguez | | 103 | 85 | 18 |
| 2003-04-24 | vs CLE | 22 | W 4-2 | 14-8 | 1 | 26,263 | Jamie Moyer | Billy Traber | Jamie Moyer | Billy Traber | Jeff Nelson | 107 | 87 | 20 |
| 2003-04-25 | vs DET | 23 | W 6-0 | 15-8 | 1 | 33,458 | Joel Pineiro | Mike Maroth | Joel Pineiro | Mike Maroth | | 113 | 87 | 26 |
| 2003-04-26 | vs DET | 24 | L 4-6 | 15-9 | 1 | 36,258 | Ryan Franklin | Gary Knotts | Jamie Walker | Ryan Franklin | Matt Anderson | 117 | 93 | 24 |
| 2003-04-27 | vs DET | 25 | W 4-3 | 16-9 | 1 | 39,678 | Freddy Garcia | Adam Bernero | Freddy Garcia | Adam Bernero | Jeff Nelson | 121 | 96 | 25 |
| 2003-04-29 | @ NYA | 26 | W 6-0 | 17-9 | 1 | 38,724 | Gil Meche | Roger Clemens | Gil Meche | Roger Clemens | | 127 | 96 | 31 |
| 2003-04-30 | @ NYA | 27 | L 5-8 | 17-10 | 2 | 30,522 | Jamie Moyer | Andy Pettitte | Andy Pettitte | Jamie Moyer | | 132 | 104 | 28 |
| 2003-05-01 | @ NYA | 28 | L 1-2 | 17-11 | 2 | 34,991 | Joel Pineiro | Mike Mussina | Mike Mussina | Joel Pineiro | Mariano Rivera | 133 | 106 | 27 |
| 2003-05-02 | @ CHA | 29 | W 9-2 | 18-11 | 1 | 13,355 | Ryan Franklin | Esteban Loaiza | Ryan Franklin | Esteban Loaiza | | 142 | 108 | 34 |
| 2003-05-03 | @ CHA | 30 | W 12-2 | 19-11 | 1 | 25,837 | Freddy Garcia | Josh Stewart | Freddy Garcia | Josh Stewart | | 154 | 110 | 44 |
| 2003-05-04 | @ CHA | 31 | W 5-1 | 20-11 | 1 | 15,413 | Gil Meche | Bartolo Colon | Gil Meche | Bartolo Colon | | 159 | 111 | 48 |
| 2003-05-06 | vs NYA | 32 | W 12-7 | 21-11 | 1 | 44,979 | Jamie Moyer | Andy Pettitte | Jamie Moyer | Andy Pettitte | | 171 | 118 | 53 |
| 2003-05-07 | vs NYA | 33 | L 2-7 | 21-12 | 1 | 43,753 | Joel Pineiro | Mike Mussina | Mike Mussina | Joel Pineiro | | 173 | 125 | 48 |
| 2003-05-08 | vs NYA | 34 | L 5-16 | 21-13 | 2 | 46,000 | Freddy Garcia | David Wells | David Wells | Freddy Garcia | | 178 | 141 | 37 |
| 2003-05-09 | vs CHA | 35 | W 6-3 | 22-13 | 2 | 38,749 | Ryan Franklin | Dan Wright | Ryan Franklin | Dan Wright | Jeff Nelson | 184 | 144 | 40 |
| 2003-05-10 | vs CHA | 36 | L 3-4 | 22-14 | 2 | 43,123 | Gil Meche | Bartolo Colon | Bartolo Colon | Gil Meche | Damaso Marte | 187 | 148 | 39 |
| 2003-05-11 | vs CHA | 37 | W 7-2 | 23-14 | 2 | 45,383 | Jamie Moyer | Mark Buehrle | Jamie Moyer | Mark Buehrle | | 194 | 150 | 44 |
| 2003-05-13 | @ CLE | 38 | W 8-3 | 24-14 | 2 | 16,721 | Joel Pineiro | Brian Anderson | Joel Pineiro | Brian Anderson | | 202 | 153 | 49 |
| 2003-05-14 | @ CLE | 39 | L 2-7 | 24-15 | 2 | 17,324 | Freddy Garcia | Jason Davis | Jason Davis | Freddy Garcia | | 204 | 160 | 44 |
| 2003-05-15 | @ CLE | 40 | W 9-1 | 25-15 | 2 | 17,889 | Ryan Franklin | Jake Westbrook | Giovanni Carrara | Jake Westbrook | | 213 | 161 | 52 |
| 2003-05-16 | @ DET | 41 | W 6-3 | 26-15 | 1 | 17,641 | Gil Meche | Jeremy Bonderman | Gil Meche | Jeremy Bonderman | Kazuhiro Sasaki | 219 | 164 | 55 |
| 2003-05-17 | @ DET | 42 | W 6-3 | 27-15 | 1 | 23,274 | Jamie Moyer | Nate Cornejo | Jamie Moyer | Nate Cornejo | Kazuhiro Sasaki | 225 | 167 | 58 |
| 2003-05-18 | @ DET | 43 | W 6-2 | 28-15 | 1 | 16,263 | Joel Pineiro | Mike Maroth | Joel Pineiro | Mike Maroth | | 231 | 169 | 62 |
| 2003-05-20 | vs KCA | 44 | W 7-4 | 29-15 | 1 | 36,423 | Ryan Franklin | Darrell May | Jeff Nelson | D.J. Carrasco | | 238 | 173 | 65 |
| 2003-05-21 | vs KCA | 45 | L 5-14 | 29-16 | 1 | 31,251 | Freddy Garcia | Chris George | Chris George | Freddy Garcia | | 243 | 187 | 56 |
| 2003-05-22 | vs KCA | 46 | W 5-1 | 30-16 | 1 | 38,322 | Gil Meche | Jeremy Affeldt | Gil Meche | Jeremy Affeldt | | 248 | 188 | 60 |
| 2003-05-23 | vs MIN | 47 | W 5-2 | 31-16 | 1 | 40,258 | Jamie Moyer | Brad Radke | Jamie Moyer | Brad Radke | Kazuhiro Sasaki | 253 | 190 | 63 |
| 2003-05-24 | vs MIN | 48 | L 2-7 | 31-17 | 1 | 45,306 | Joel Pineiro | Kyle Lohse | Kyle Lohse | Joel Pineiro | | 255 | 197 | 58 |
| 2003-05-25 | vs MIN | 49 | L 1-3 | 31-18 | 1 | 45,213 | Ryan Franklin | Rick Reed | Rick Reed | Ryan Franklin | Eddie Guardado | 256 | 200 | 56 |
| 2003-05-27 | @ KCA | 50 | W 15-7 | 32-18 | 1 | 14,154 | Freddy Garcia | Chris George | Freddy Garcia | Chris George | | 271 | 207 | 64 |
| 2003-05-28 | @ KCA | 51 | W 5-2 | 33-18 | 1 | 14,928 | Jamie Moyer | Jeremy Affeldt | Jamie Moyer | Jeremy Affeldt | Kazuhiro Sasaki | 276 | 209 | 67 |
| 2003-05-29 | @ MIN | 52 | W 10-6 | 34-18 | 1 | 16,409 | Gil Meche | Brad Radke | Gil Meche | Brad Radke | | 286 | 215 | 71 |
| 2003-05-30 | @ MIN | 53 | W 6-0 | 35-18 | 1 | 30,179 | Joel Pineiro | Kyle Lohse | Joel Pineiro | Kyle Lohse | | 292 | 215 | 77 |
| 2003-05-31 | @ MIN | 54 | W 5-2 | 36-18 | 1 | 22,995 | Ryan Franklin | Rick Reed | Ryan Franklin | Rick Reed | Kazuhiro Sasaki | 297 | 217 | 80 |
| 2003-06-01 | @ MIN | 55 | W 9-5 | 37-18 | 1 | 18,754 | Freddy Garcia | Kenny Rogers | Freddy Garcia | Kenny Rogers | | 306 | 222 | 84 |
| 2003-06-03 | @ PHI | 56 | W 4-0 | 38-18 | 1 | 18,029 | Jamie Moyer | Kevin Millwood | Jamie Moyer | Kevin Millwood | | 310 | 222 | 88 |
| 2003-06-04 | @ PHI | 57 | W 7-2 | 39-18 | 1 | 16,232 | Gil Meche | Vicente Padilla | Gil Meche | Vicente Padilla | | 317 | 224 | 93 |
| 2003-06-05 | @ PHI | 58 | W 5-4 | 40-18 | 1 | 21,145 | Joel Pineiro | Brandon Duckworth | Julio Mateo | Jose Mesa | Kazuhiro Sasaki | 322 | 228 | 94 |
| 2003-06-06 | @ NYN | 59 | L 2-3 | 40-19 | 1 | 26,684 | Ryan Franklin | Jae Weong Seo | Jae Weong Seo | Ryan Franklin | Armando Benitez | 324 | 231 | 93 |
| 2003-06-08 | @ NYN | 60 | W 13-1 | 42-19 | 1 | 0 | Freddy Garcia | Al Leiter | Freddy Garcia | Al Leiter | | 337 | 232 | 105 |
| 2003-06-08 | @ NYN | 61 | W 7-0 | 42-19 | 1 | 39,820 | Jamie Moyer | Michael Bacsik | Jamie Moyer | Michael Bacsik | | 344 | 232 | 112 |
| 2003-06-10 | vs MON | 62 | L 3-7 | 42-20 | 1 | 34,811 | Gil Meche | Javier Vazquez | Javier Vazquez | Gil Meche | Luis Ayala | 347 | 239 | 108 |
| 2003-06-11 | vs MON | 63 | L 1-3 | 42-21 | 1 | 32,853 | Joel Pineiro | Livan Hernandez | Livan Hernandez | Joel Pineiro | Rocky Biddle | 348 | 242 | 106 |
| 2003-06-12 | vs MON | 64 | W 1-0 | 43-21 | 1 | 33,761 | Ryan Franklin | Claudio Vargas | Ryan Franklin | Claudio Vargas | Arthur Rhodes | 349 | 242 | 107 |
| 2003-06-13 | vs ATL | 65 | W 2-1 | 44-21 | 1 | 45,791 | Freddy Garcia | Russ Ortiz | Freddy Garcia | Russ Ortiz | Jeff Nelson | 351 | 243 | 108 |
| 2003-06-14 | vs ATL | 66 | L 1-3 | 44-22 | 1 | 45,971 | Jamie Moyer | Mike Hampton | Mike Hampton | Jamie Moyer | John Smoltz | 352 | 246 | 106 |
| 2003-06-15 | vs ATL | 67 | W 2-1 | 45-22 | 1 | 45,732 | Gil Meche | Greg Maddux | Gil Meche | Greg Maddux | Jeff Nelson | 354 | 247 | 107 |
| 2003-06-16 | vs ANA | 68 | W 6-3 | 46-22 | 1 | 41,599 | Joel Pineiro | John Lackey | Joel Pineiro | John Lackey | Arthur Rhodes | 360 | 250 | 110 |
| 2003-06-17 | vs ANA | 69 | W 8-4 | 47-22 | 1 | 39,054 | Ryan Franklin | Kevin Appier | Ryan Franklin | Kevin Appier | | 368 | 254 | 114 |
| 2003-06-18 | vs ANA | 70 | W 2-0 | 48-22 | 1 | 43,473 | Freddy Garcia | Aaron Sele | Freddy Garcia | Aaron Sele | Arthur Rhodes | 370 | 254 | 116 |
| 2003-06-19 | vs ANA | 71 | L 0-2 | 48-23 | 1 | 45,758 | Jamie Moyer | Ramon Ortiz | Ramon Ortiz | Jamie Moyer | Troy Percival | 370 | 256 | 114 |
| 2003-06-20 | @ SDN | 72 | L 3-5 | 48-24 | 1 | 23,500 | Gil Meche | Oliver Perez | Mike Matthews | Jeff Nelson | | 373 | 261 | 112 |
| 2003-06-21 | @ SDN | 73 | W 4-2 | 49-24 | 1 | 38,243 | Joel Pineiro | Adam Eaton | Joel Pineiro | Adam Eaton | Shigetoshi Hasegawa | 377 | 263 | 114 |
| 2003-06-22 | @ SDN | 74 | L 1-3 | 49-25 | 1 | 27,163 | Ryan Franklin | Jake Peavy | Jake Peavy | Ryan Franklin | Rod Beck | 378 | 266 | 112 |
| 2003-06-24 | @ ANA | 75 | W 6-4 | 50-25 | 1 | 39,121 | Freddy Garcia | Aaron Sele | Freddy Garcia | Aaron Sele | Jeff Nelson | 384 | 270 | 114 |
| 2003-06-25 | @ ANA | 76 | L 3-6 | 50-26 | 1 | 40,651 | Jamie Moyer | Ramon Ortiz | Ramon Ortiz | Jamie Moyer | Troy Percival | 387 | 276 | 111 |
| 2003-06-26 | @ ANA | 77 | W 10-6 | 51-26 | 1 | 32,889 | Gil Meche | Jarrod Washburn | Gil Meche | Jarrod Washburn | Shigetoshi Hasegawa | 397 | 282 | 115 |
| 2003-06-27 | vs SDN | 78 | W 8-2 | 52-26 | 1 | 45,529 | Joel Pineiro | Adam Eaton | Joel Pineiro | Adam Eaton | | 405 | 284 | 121 |
| 2003-06-28 | vs SDN | 79 | L 0-6 | 52-27 | 1 | 45,326 | Ryan Franklin | Jake Peavy | Jake Peavy | Ryan Franklin | | 405 | 290 | 115 |
| 2003-06-29 | vs SDN | 80 | L 6-8 | 52-28 | 1 | 45,641 | Freddy Garcia | Kevin Jarvis | Rod Beck | Arthur Rhodes | Jay Witasick | 411 | 298 | 113 |
| 2003-06-30 | @ OAK | 81 | W 3-1 | 53-28 | 1 | 24,831 | Jamie Moyer | Aaron Harang | Jamie Moyer | Aaron Harang | Jeff Nelson | 414 | 299 | 115 |
| 2003-07-01 | @ OAK | 82 | L 2-3 | 53-29 | 1 | 20,233 | Gil Meche | Tim Hudson | Keith Foulke | Jeff Nelson | | 416 | 302 | 114 |
| 2003-07-02 | @ OAK | 83 | W 13-0 | 54-29 | 1 | 33,420 | Joel Pineiro | Ted Lilly | Joel Pineiro | Ted Lilly | | 429 | 302 | 127 |
| 2003-07-03 | @ OAK | 84 | L 2-5 | 54-30 | 1 | 19,612 | Ryan Franklin | Barry Zito | Barry Zito | Ryan Franklin | Keith Foulke | 431 | 307 | 124 |
| 2003-07-04 | @ TEX | 85 | L 3-7 | 54-31 | 1 | 49,530 | Freddy Garcia | Victor Santos | R.A. Dickey | Freddy Garcia | Ugueth Urbina | 434 | 314 | 120 |
| 2003-07-05 | @ TEX | 86 | W 3-2 | 55-31 | 1 | 31,332 | Jamie Moyer | John Thomson | Rafael Soriano | Ugueth Urbina | Shigetoshi Hasegawa | 437 | 316 | 121 |
| 2003-07-06 | @ TEX | 87 | L 1-5 | 55-32 | 1 | 18,114 | Gil Meche | Ismael Valdez | Ismael Valdez | Gil Meche | | 438 | 321 | 117 |
| 2003-07-08 | vs BAL | 88 | W 6-5 | 56-32 | 1 | 37,327 | Joel Pineiro | Jason Johnson | Joel Pineiro | Jason Johnson | Shigetoshi Hasegawa | 444 | 326 | 118 |
| 2003-07-09 | vs BAL | 89 | L 2-7 | 56-33 | 1 | 39,563 | Ryan Franklin | Rick Helling | Rick Helling | Ryan Franklin | | 446 | 333 | 113 |
| 2003-07-10 | vs BAL | 90 | L 1-4 | 56-34 | 1 | 35,801 | Freddy Garcia | Sidney Ponson | Sidney Ponson | Freddy Garcia | | 447 | 337 | 110 |
| 2003-07-11 | vs TBA | 91 | W 4-3 | 57-34 | 1 | 45,156 | Jamie Moyer | Geremi Gonzalez | Jamie Moyer | Travis Harper | Shigetoshi Hasegawa | 451 | 340 | 111 |
| 2003-07-12 | vs TBA | 92 | L 5-6 | 57-35 | 1 | 45,655 | Gil Meche | Victor Zambrano | Victor Zambrano | Gil Meche | Lance Carter | 456 | 346 | 110 |
| 2003-07-13 | vs TBA | 93 | W 13-2 | 58-35 | 1 | 45,602 | Joel Pineiro | Jason Standridge | Joel Pineiro | Jason Standridge | | 469 | 348 | 121 |
| 2003-07-17 | @ KCA | 94 | L 1-7 | 58-36 | 1 | 22,481 | Freddy Garcia | Jose Lima | Jose Lima | Freddy Garcia | | 470 | 355 | 115 |
| 2003-07-18 | @ KCA | 95 | W 6-3 | 59-36 | 1 | 30,698 | Ryan Franklin | Jeremy Affeldt | Arthur Rhodes | Mike MacDougal | Shigetoshi Hasegawa | 476 | 358 | 118 |
| 2003-07-19 | @ KCA | 96 | L 1-5 | 59-37 | 1 | 39,808 | Gil Meche | Darrell May | Darrell May | Gil Meche | | 477 | 363 | 114 |
| 2003-07-20 | @ KCA | 97 | L 5-7 | 59-38 | 1 | 16,880 | Jamie Moyer | Runelvys Hernandez | Kris Wilson | Arthur Rhodes | | 482 | 370 | 112 |
| 2003-07-21 | @ MIN | 98 | L 4-5 | 59-39 | 1 | 20,306 | Joel Pineiro | Kyle Lohse | Juan Rincon | Arthur Rhodes | Eddie Guardado | 486 | 375 | 111 |
| 2003-07-22 | @ MIN | 99 | W 10-8 | 60-39 | 1 | 22,229 | Freddy Garcia | Rick Reed | Julio Mateo | Joe Mays | Shigetoshi Hasegawa | 496 | 383 | 113 |
| 2003-07-23 | vs OAK | 100 | W 6-0 | 61-39 | 1 | 41,959 | Ryan Franklin | Barry Zito | Ryan Franklin | Barry Zito | | 502 | 383 | 119 |
| 2003-07-24 | vs OAK | 101 | L 0-3 | 61-40 | 1 | 42,730 | Gil Meche | Mark Mulder | Mark Mulder | Gil Meche | Keith Foulke | 502 | 386 | 116 |
| 2003-07-25 | vs TEX | 102 | W 11-5 | 62-40 | 1 | 43,871 | Jamie Moyer | Robert Ellis | Jamie Moyer | Robert Ellis | Rafael Soriano | 513 | 391 | 122 |
| 2003-07-26 | vs TEX | 103 | W 4-0 | 63-40 | 1 | 45,934 | Joel Pineiro | Colby Lewis | Joel Pineiro | Colby Lewis | | 517 | 391 | 126 |
| 2003-07-27 | vs TEX | 104 | L 3-7 | 63-41 | 1 | 45,355 | Freddy Garcia | John Thomson | John Thomson | Freddy Garcia | | 520 | 398 | 122 |
| 2003-07-28 | vs TEX | 105 | L 1-10 | 63-42 | 1 | 44,415 | Ryan Franklin | Joaquin Benoit | Joaquin Benoit | Ryan Franklin | | 521 | 408 | 113 |
| 2003-07-29 | vs DET | 106 | W 11-5 | 64-42 | 1 | 30,732 | Gil Meche | Matt Roney | Gil Meche | Matt Roney | | 532 | 413 | 119 |
| 2003-07-30 | vs DET | 107 | W 13-3 | 65-42 | 1 | 35,800 | Jamie Moyer | Nate Cornejo | Jamie Moyer | Nate Cornejo | | 545 | 416 | 129 |
| 2003-07-31 | vs DET | 108 | W 4-0 | 66-42 | 1 | 43,596 | Joel Pineiro | Wil Ledezma | Joel Pineiro | Wil Ledezma | | 549 | 416 | 133 |
| 2003-08-01 | vs CHA | 109 | L 1-12 | 66-43 | 1 | 39,337 | Freddy Garcia | Bartolo Colon | Bartolo Colon | Freddy Garcia | | 550 | 428 | 122 |
| 2003-08-02 | vs CHA | 110 | W 10-0 | 67-43 | 1 | 45,719 | Ryan Franklin | Dan Wright | Ryan Franklin | Dan Wright | | 560 | 428 | 132 |
| 2003-08-03 | vs CHA | 111 | W 8-2 | 68-43 | 1 | 45,632 | Gil Meche | Mark Buehrle | Gil Meche | Mark Buehrle | | 568 | 430 | 138 |
| 2003-08-05 | @ CLE | 112 | W 2-1 | 69-43 | 1 | 22,300 | Jamie Moyer | CC Sabathia | Jamie Moyer | CC Sabathia | Shigetoshi Hasegawa | 570 | 431 | 139 |
| 2003-08-06 | @ CLE | 113 | L 6-10 | 69-44 | 1 | 23,282 | Joel Pineiro | Jake Westbrook | Jake Westbrook | Joel Pineiro | | 576 | 441 | 135 |
| 2003-08-07 | @ CLE | 114 | L 0-3 | 69-45 | 1 | 21,141 | Freddy Garcia | Billy Traber | Billy Traber | Freddy Garcia | Danys Baez | 576 | 444 | 132 |
| 2003-08-08 | @ NYA | 115 | L 7-9 | 69-46 | 1 | 52,793 | Ryan Franklin | Jeff Weaver | Sterling Hitchcock | Ryan Franklin | Mariano Rivera | 583 | 453 | 130 |
| 2003-08-09 | @ NYA | 116 | W 2-1 | 70-46 | 1 | 54,945 | Gil Meche | Andy Pettitte | Gil Meche | Andy Pettitte | Shigetoshi Hasegawa | 585 | 454 | 131 |
| 2003-08-10 | @ NYA | 117 | W 8-6 | 71-46 | 1 | 54,828 | Jamie Moyer | Roger Clemens | Rafael Soriano | Antonio Osuna | Shigetoshi Hasegawa | 593 | 460 | 133 |
| 2003-08-11 | vs TOR | 118 | L 3-5 | 71-47 | 1 | 44,922 | Joel Pineiro | Mark Hendrickson | Mark Hendrickson | Joel Pineiro | Aquilino Lopez | 596 | 465 | 131 |
| 2003-08-12 | vs TOR | 119 | W 3-1 | 72-47 | 1 | 37,018 | Freddy Garcia | Roy Halladay | Freddy Garcia | Roy Halladay | Shigetoshi Hasegawa | 599 | 466 | 133 |
| 2003-08-13 | vs TOR | 120 | W 13-6 | 73-47 | 1 | 37,066 | Ryan Franklin | Corey Thurman | Julio Mateo | Jason Kershner | | 612 | 472 | 140 |
| 2003-08-14 | vs TOR | 121 | L 2-5 | 73-48 | 1 | 41,945 | Gil Meche | Kelvim Escobar | Kelvim Escobar | Gil Meche | Aquilino Lopez | 614 | 477 | 137 |
| 2003-08-15 | vs BOS | 122 | W 10-5 | 74-48 | 1 | 46,171 | Jamie Moyer | Jeff Suppan | Julio Mateo | Mike Timlin | Shigetoshi Hasegawa | 624 | 482 | 142 |
| 2003-08-16 | vs BOS | 123 | L 1-5 | 74-49 | 1 | 46,100 | Joel Pineiro | Pedro Martinez | Pedro Martinez | Joel Pineiro | | 625 | 487 | 138 |
| 2003-08-17 | vs BOS | 124 | W 3-1 | 75-49 | 1 | 46,105 | Freddy Garcia | John Burkett | Freddy Garcia | John Burkett | Shigetoshi Hasegawa | 628 | 488 | 140 |
| 2003-08-19 | @ TOR | 125 | W 9-1 | 76-49 | 1 | 24,025 | Ryan Franklin | Kelvim Escobar | Ryan Franklin | Kelvim Escobar | | 637 | 489 | 148 |
| 2003-08-20 | @ TOR | 126 | L 2-5 | 76-50 | 1 | 21,588 | Gil Meche | Josh Towers | Josh Towers | Gil Meche | | 639 | 494 | 145 |
| 2003-08-21 | @ TOR | 127 | L 3-7 | 76-51 | 1 | 20,111 | Jamie Moyer | Mark Hendrickson | Mark Hendrickson | Jamie Moyer | | 642 | 501 | 141 |
| 2003-08-22 | @ BOS | 128 | L 4-6 | 76-52 | 1 | 34,379 | Joel Pineiro | Jeff Suppan | Jeff Suppan | Joel Pineiro | Byung-Hyun Kim | 646 | 507 | 139 |
| 2003-08-23 | @ BOS | 129 | L 6-7 | 76-53 | 1 | 34,488 | Freddy Garcia | John Burkett | Mike Timlin | Kazuhiro Sasaki | | 652 | 514 | 138 |
| 2003-08-24 | @ BOS | 130 | L 1-6 | 76-54 | 1 | 34,344 | Ryan Franklin | Derek Lowe | Derek Lowe | Ryan Franklin | | 653 | 520 | 133 |
| 2003-08-25 | @ BOS | 131 | L 1-8 | 76-55 | 2 | 33,007 | Gil Meche | Pedro Martinez | Pedro Martinez | Gil Meche | Bronson Arroyo | 654 | 528 | 126 |
| 2003-08-26 | vs TBA | 132 | W 9-3 | 77-55 | 2 | 43,287 | Jamie Moyer | Victor Zambrano | Jamie Moyer | Victor Zambrano | | 663 | 531 | 132 |
| 2003-08-27 | vs TBA | 133 | L 4-8 | 77-56 | 2 | 42,442 | Joel Pineiro | Chad Gaudin | Doug Waechter | Joel Pineiro | | 667 | 539 | 128 |
| 2003-08-28 | vs TBA | 134 | L 2-3 | 77-57 | 2 | 42,563 | Freddy Garcia | Jorge Sosa | Travis Harper | Shigetoshi Hasegawa | Lance Carter | 669 | 542 | 127 |
| 2003-08-29 | vs BAL | 135 | W 3-2 | 78-57 | 2 | 43,365 | Ryan Franklin | Eric DuBose | Rafael Soriano | Jorge Julio | | 672 | 544 | 128 |
| 2003-08-30 | vs BAL | 136 | W 13-1 | 79-57 | 2 | 45,618 | Gil Meche | Damian Moss | Gil Meche | Damian Moss | | 685 | 545 | 140 |
| 2003-08-31 | vs BAL | 137 | W 3-0 | 80-57 | 2 | 45,760 | Jamie Moyer | Jason Johnson | Jamie Moyer | Jason Johnson | Shigetoshi Hasegawa | 688 | 545 | 143 |
| 2003-09-02 | @ TBA | 138 | W 10-8 | 81-57 | 2 | 8,237 | Joel Pineiro | Victor Zambrano | Shigetoshi Hasegawa | Lance Carter | | 698 | 553 | 145 |
| 2003-09-03 | @ TBA | 139 | L 0-7 | 81-58 | 2 | 8,696 | Freddy Garcia | Doug Waechter | Doug Waechter | Freddy Garcia | | 698 | 560 | 138 |
| 2003-09-04 | @ TBA | 140 | L 0-1 | 81-59 | 2 | 8,486 | Ryan Franklin | Jorge Sosa | Jorge Sosa | Ryan Franklin | | 698 | 561 | 137 |
| 2003-09-05 | @ BAL | 141 | W 6-4 | 82-59 | 2 | 27,417 | Gil Meche | Jason Johnson | Arthur Rhodes | Kerry Ligtenberg | | 704 | 565 | 139 |
| 2003-09-06 | @ BAL | 142 | L 1-3 | 82-60 | 2 | 43,793 | Jamie Moyer | Eric DuBose | Eric DuBose | Jamie Moyer | Jorge Julio | 705 | 568 | 137 |
| 2003-09-07 | @ BAL | 143 | L 1-2 | 82-61 | 2 | 36,897 | Freddy Garcia | Pat Hentgen | Pat Hentgen | Freddy Garcia | Jorge Julio | 706 | 570 | 136 |
| 2003-09-09 | vs TEX | 144 | L 4-5 | 82-62 | 2 | 37,707 | Ryan Franklin | Tony Mounce | Ron Mahay | Shigetoshi Hasegawa | Francisco Cordero | 710 | 575 | 135 |
| 2003-09-10 | vs TEX | 145 | W 3-1 | 83-62 | 2 | 36,450 | Joel Pineiro | John Thomson | Joel Pineiro | John Thomson | | 713 | 576 | 137 |
| 2003-09-11 | vs TEX | 146 | W 8-2 | 84-62 | 2 | 35,729 | Gil Meche | Mickey Callaway | Gil Meche | Mickey Callaway | | 721 | 578 | 143 |
| 2003-09-12 | vs ANA | 147 | W 7-4 | 85-62 | 2 | 41,601 | Jamie Moyer | John Lackey | Jamie Moyer | John Lackey | Shigetoshi Hasegawa | 728 | 582 | 146 |
| 2003-09-13 | vs ANA | 148 | W 5-1 | 86-62 | 2 | 45,552 | Freddy Garcia | Aaron Sele | Freddy Garcia | Francisco Rodriguez | | 733 | 583 | 150 |
| 2003-09-14 | vs ANA | 149 | L 1-2 | 86-63 | 2 | 45,861 | Ryan Franklin | Kevin Gregg | Kevin Gregg | Ryan Franklin | Troy Percival | 734 | 585 | 149 |
| 2003-09-15 | @ TEX | 150 | L 4-6 | 86-64 | 2 | 22,041 | Joel Pineiro | Colby Lewis | Colby Lewis | Joel Pineiro | Francisco Cordero | 738 | 591 | 147 |
| 2003-09-16 | @ TEX | 151 | L 5-10 | 86-65 | 2 | 16,134 | Gil Meche | John Thomson | John Thomson | Gil Meche | | 743 | 601 | 142 |
| 2003-09-17 | @ TEX | 152 | W 5-1 | 87-65 | 2 | 21,016 | Jamie Moyer | Ryan Drese | Jamie Moyer | Ryan Drese | | 748 | 602 | 146 |
| 2003-09-18 | @ TEX | 153 | L 1-2 | 87-66 | 2 | 16,231 | Freddy Garcia | Joaquin Benoit | Francisco Cordero | Shigetoshi Hasegawa | | 749 | 604 | 145 |
| 2003-09-19 | @ OAK | 154 | W 6-1 | 88-66 | 2 | 41,035 | Ryan Franklin | Tim Hudson | Ryan Franklin | Tim Hudson | | 755 | 605 | 150 |
| 2003-09-20 | @ OAK | 155 | W 9-3 | 89-66 | 2 | 40,226 | Joel Pineiro | Justin Duchscherer | Joel Pineiro | Justin Duchscherer | | 764 | 608 | 156 |
| 2003-09-21 | @ OAK | 156 | L 0-12 | 89-67 | 2 | 40,643 | Gil Meche | Ted Lilly | Ted Lilly | Gil Meche | | 764 | 620 | 144 |
| 2003-09-22 | @ ANA | 157 | W 5-1 | 90-67 | 2 | 35,537 | Jamie Moyer | Jarrod Washburn | Jamie Moyer | Jarrod Washburn | | 769 | 621 | 148 |
| 2003-09-23 | @ ANA | 158 | L 1-2 | 90-68 | 2 | 37,645 | Freddy Garcia | Scot Shields | Francisco Rodriguez | Shigetoshi Hasegawa | | 770 | 623 | 147 |
| 2003-09-24 | @ ANA | 159 | L 0-4 | 90-69 | 2 | 30,917 | Gil Meche | John Lackey | John Lackey | Gil Meche | | 770 | 627 | 143 |
| 2003-09-26 | vs OAK | 160 | W 9-3 | 91-69 | 2 | 45,519 | Joel Pineiro | Mike Wood | Joel Pineiro | Mike Wood | Julio Mateo | 779 | 630 | 149 |
| 2003-09-27 | vs OAK | 161 | W 7-4 | 92-69 | 2 | 45,483 | Ryan Franklin | Barry Zito | Ryan Franklin | Chad Bradford | Shigetoshi Hasegawa | 786 | 634 | 152 |
| 2003-09-28 | vs OAK | 162 | W 9-3 | 93-69 | 2 | 45,719 | Jamie Moyer | Ted Lilly | Jamie Moyer | Ted Lilly | | 795 | 637 | 158 |