In Major League Baseball (MLB), records play an integral part in evaluating a player's impact on the sport. Holding a career record almost guarantees a player eventual entry into the Baseball Hall of Fame because it represents both longevity and consistency over a long period of time.
| Record | Player | # |
|---|---|---|
| Most wins | Cy Young | 511 |
| Most losses | Cy Young | 316 |
| Most no-hitters | Nolan Ryan | 7 |
| Most strikeouts | Nolan Ryan | 5,714 |
| Most shutouts | Walter Johnson | 110 |
| Most starts | Cy Young | 815 |
| Most pickoffs | Steve Carlton | 144 |
| Most innings pitched | Cy Young | 7,354+2⁄3 |
| Most hit batsmen | Gus Weyhing | 278 |
| Most home runs allowed | Jamie Moyer | 522 |
| Most complete games | Cy Young | 749 |
| Lowest earned-run average | Ed Walsh | 1.82 |
| Lowest walks plus hits per inning pitched | Addie Joss | .968 |
| Most saves | Mariano Rivera | 652 |
| Highest win–loss percentage | Spud Chandler | 71.7% |
| Most games | Jesse Orosco | 1,252 |
| Most consecutive scoreless innings pitched | Orel Hershiser | 59 [a] |
(if different from overall records)
| Record | Player | # |
|---|---|---|
| Most wins | Warren Spahn | 363 |
| Most losses | Nolan Ryan | 292 |
| Lowest earned-run average | Mariano Rivera | 2.21 |
| Most shutouts | Warren Spahn | 63 |
| Most innings pitched | Phil Niekro | 5,404+1⁄3 |
| Most complete games | Warren Spahn | 382 |
| Lowest Walks plus hits per inning pitched | Mariano Rivera | 1.000 |