Single Season Winning % Leaders - Min 150 innings
| Rank | Player | Year | Team | W | L | W-L% | ERA | G | GS | GF | CG | SH | SV | SV% | IP | BB | SO | WHIP | BR9 | HR9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Pedro Martinez | 1997 | SPS | 21 | 5 | .808 | 1.87 | 36 | 36 | 0 | 3 | 2 | 0 | 0 | 241 | 63 | 305 | 0.876 | 7.88 | 0.93 |
| 2 | Billy Pierce | 1949 | PBP | 16 | 4 | .800 | 2.17 | 75 | 15 | 60 | 1 | 0 | 2 | 40 | 182.2 | 121 | 102 | 1.363 | 12.27 | 0.30 |
| 3 | Wilcy Moore | 1927 | MIT | 22 | 6 | .786 | 2.19 | 78 | 5 | 73 | 1 | 0 | 13 | 52 | 201.2 | 57 | 75 | 1.250 | 11.25 | 0.13 |
| 4 | Jacob Degrom | 2015 | IMG | 10 | 3 | .769 | 2.45 | 26 | 26 | 0 | 1 | 1 | 0 | 0 | 176.1 | 43 | 182 | 0.953 | 8.57 | 0.97 |
| 5 | Harry Rhodes | 1949 | THD | 16 | 5 | .762 | 3.47 | 33 | 29 | 4 | 3 | 1 | 1 | 50 | 187 | 96 | 58 | 1.476 | 13.28 | 0.91 |
| 6 | John Smoltz | 1997 | IMG | 19 | 6 | .760 | 2.62 | 33 | 33 | 0 | 5 | 1 | 0 | 0 | 247.1 | 55 | 249 | 1.108 | 9.97 | 0.84 |
| 7 | Scott Erickson | 1997 | IMG | 15 | 5 | .750 | 2.79 | 32 | 32 | 0 | 1 | 1 | 0 | 0 | 222.1 | 56 | 126 | 1.088 | 9.80 | 0.81 |
| Dolly Cooper | 1927 | DIN | 18 | 6 | .750 | 3.38 | 27 | 27 | 0 | 5 | 0 | 0 | 0 | 200 | 45 | 32 | 1.240 | 11.16 | 0.41 | |
| 9 | Gaylord Perry | 1974 | BBC | 20 | 7 | .741 | 3.40 | 35 | 35 | 0 | 11 | 3 | 0 | 0 | 270.1 | 96 | 187 | 1.158 | 10.42 | 0.87 |
| 10 | Kevin Brown | 1997 | HRH | 17 | 6 | .739 | 1.94 | 34 | 34 | 0 | 4 | 2 | 0 | 0 | 236.1 | 82 | 187 | 1.058 | 9.52 | 0.30 |
| Max Manning | 1949 | THD | 17 | 6 | .739 | 2.35 | 55 | 18 | 37 | 4 | 1 | 2 | 22 | 206.2 | 57 | 45 | 1.108 | 9.97 | 0.74 | |
| 12 | Colby Lewis | 2015 | PVD | 11 | 4 | .733 | 3.83 | 30 | 30 | 0 | 1 | 1 | 0 | 0 | 185.2 | 53 | 138 | 1.233 | 11.10 | 1.16 |
| 13 | Tommy Thomas | 1927 | THD | 24 | 9 | .727 | 2.82 | 41 | 41 | 0 | 15 | 4 | 0 | 0 | 319.2 | 119 | 117 | 1.233 | 11.09 | 0.39 |
| Glenn Abbott | 1977 | BUM | 8 | 3 | .727 | 4.18 | 60 | 5 | 55 | 0 | 0 | 3 | 100 | 153 | 56 | 77 | 1.431 | 12.88 | 1.18 | |
| 15 | Zack Greinke | 2015 | MNL | 18 | 7 | .720 | 2.30 | 29 | 29 | 0 | 6 | 1 | 0 | 0 | 222.2 | 49 | 182 | 0.862 | 7.76 | 0.73 |
| Clayton Kershaw | 2015 | QCK | 18 | 7 | .720 | 2.91 | 34 | 33 | 1 | 6 | 3 | 0 | 0 | 231.2 | 52 | 293 | 1.019 | 9.17 | 0.89 | |
| Corey Kluber | 2015 | CIR | 18 | 7 | .720 | 3.16 | 32 | 32 | 0 | 2 | 2 | 0 | 0 | 216.2 | 74 | 236 | 1.195 | 10.76 | 1.12 | |
| 18 | Phil Niekro | 1974 | CIR | 15 | 6 | .714 | 2.58 | 28 | 28 | 0 | 14 | 7 | 0 | 0 | 227 | 83 | 152 | 1.106 | 9.95 | 0.48 |
| Dave Freisleben | 1974 | SEP | 10 | 4 | .714 | 2.97 | 25 | 25 | 0 | 4 | 2 | 0 | 0 | 163.2 | 72 | 115 | 1.265 | 11.38 | 0.49 | |
| 20 | Greg Maddux | 1997 | HRH | 17 | 7 | .708 | 2.87 | 34 | 34 | 0 | 0 | 0 | 0 | 0 | 226 | 48 | 153 | 1.066 | 9.60 | 0.80 |
| Frank Tanana | 1977 | MWB | 17 | 7 | .708 | 3.00 | 35 | 35 | 0 | 6 | 1 | 0 | 0 | 237.1 | 67 | 211 | 1.108 | 9.97 | 0.68 | |
| 22 | Joe Niekro | 1977 | THD | 12 | 5 | .706 | 3.03 | 30 | 29 | 1 | 0 | 0 | 0 | 0 | 181 | 75 | 95 | 1.293 | 11.64 | 0.90 |
| Andy Benes | 1997 | SSL | 12 | 5 | .706 | 3.06 | 26 | 26 | 0 | 0 | 0 | 0 | 0 | 164.2 | 73 | 157 | 1.263 | 11.37 | 0.66 | |
| Brett Anderson | 2015 | SRR | 12 | 5 | .706 | 3.12 | 30 | 30 | 0 | 0 | 0 | 0 | 0 | 161.2 | 66 | 105 | 1.410 | 12.69 | 0.89 | |
| 25 | Steve Rogers | 1977 | COL | 21 | 9 | .700 | 3.27 | 37 | 37 | 0 | 9 | 2 | 0 | 0 | 275.1 | 92 | 203 | 1.271 | 11.44 | 0.78 |
| 26 | Sonny Gray | 2015 | IMG | 16 | 7 | .696 | 2.10 | 30 | 30 | 0 | 0 | 0 | 0 | 0 | 206 | 49 | 152 | 0.879 | 7.91 | 0.66 |
| Mike Scott | 1987 | QBS | 16 | 7 | .696 | 2.62 | 32 | 32 | 0 | 6 | 0 | 0 | 0 | 230.1 | 74 | 206 | 1.059 | 9.53 | 0.78 | |
| Mickey Lolich | 1974 | SEP | 16 | 7 | .696 | 4.44 | 33 | 33 | 0 | 3 | 0 | 0 | 0 | 211 | 43 | 134 | 1.322 | 11.90 | 1.32 | |
| 29 | Potato Piloto | 1949 | DIN | 9 | 4 | .692 | 3.06 | 86 | 5 | 81 | 0 | 0 | 8 | 73 | 153 | 56 | 50 | 1.268 | 11.41 | 0.59 |
| Teddy Higuera | 1987 | DPC | 18 | 8 | .692 | 4.27 | 35 | 35 | 0 | 4 | 2 | 0 | 0 | 232 | 95 | 210 | 1.353 | 12.18 | 0.78 | |
| 31 | Tom Seaver | 1977 | COL | 20 | 9 | .690 | 3.68 | 37 | 37 | 0 | 0 | 0 | 0 | 0 | 251.2 | 83 | 179 | 1.291 | 11.62 | 0.93 |
| 32 | Carlos Martinez | 2015 | SSL | 11 | 5 | .688 | 3.21 | 34 | 28 | 6 | 0 | 0 | 0 | 0 | 174 | 72 | 146 | 1.345 | 12.10 | 1.09 |
| 33 | Bill Stafford | 1961 | QQB | 13 | 6 | .684 | 3.53 | 27 | 27 | 0 | 1 | 0 | 0 | 0 | 168.1 | 57 | 78 | 1.319 | 11.87 | 0.91 |
| Charlie Leibrandt | 1987 | SAT | 13 | 6 | .684 | 3.61 | 30 | 30 | 0 | 4 | 1 | 0 | 0 | 209.2 | 79 | 140 | 1.245 | 11.20 | 0.99 | |
| Kyle Gibson | 2015 | PVD | 13 | 6 | .684 | 3.70 | 31 | 31 | 0 | 0 | 0 | 0 | 0 | 185 | 60 | 116 | 1.292 | 11.63 | 0.88 | |
| Paul Splittorff | 1977 | MWB | 13 | 6 | .684 | 3.88 | 33 | 33 | 0 | 2 | 0 | 0 | 0 | 181 | 95 | 84 | 1.602 | 14.42 | 0.30 | |
| Mike Mccormick | 1961 | QQB | 13 | 6 | .684 | 4.76 | 37 | 37 | 0 | 0 | 0 | 0 | 0 | 221 | 91 | 139 | 1.376 | 12.38 | 1.34 | |
| Rick Rhoden | 1977 | SSL | 13 | 6 | .684 | 5.22 | 26 | 26 | 0 | 3 | 0 | 0 | 0 | 179.1 | 74 | 112 | 1.556 | 14.00 | 1.20 | |
| 39 | Pat Scantlebury | 1949 | SRR | 17 | 8 | .680 | 3.98 | 49 | 34 | 15 | 1 | 0 | 0 | 0 | 242 | 88 | 87 | 1.479 | 13.31 | 0.93 |
| Garland Braxton | 1927 | COL | 17 | 8 | .680 | 4.23 | 93 | 0 | 93 | 0 | 0 | 22 | 61 | 157.1 | 51 | 90 | 1.373 | 12.36 | 0.46 | |
| 41 | Bob Lemon | 1949 | SPS | 25 | 12 | .676 | 3.04 | 42 | 40 | 2 | 12 | 3 | 0 | 0 | 308.1 | 155 | 167 | 1.242 | 11.18 | 0.90 |
| 42 | Dolf Luque | 1927 | MNL | 16 | 8 | .667 | 2.96 | 32 | 28 | 4 | 6 | 1 | 0 | 0 | 224.2 | 53 | 72 | 1.255 | 11.30 | 0.40 |
| Oscar Levis | 1927 | DIN | 14 | 7 | .667 | 3.00 | 27 | 27 | 0 | 8 | 3 | 0 | 0 | 204 | 52 | 40 | 1.123 | 10.10 | 0.62 | |
| Mountain Drop Mitchell | 1927 | MNL | 10 | 5 | .667 | 3.09 | 34 | 18 | 16 | 6 | 1 | 2 | 40 | 166 | 59 | 35 | 1.349 | 12.14 | 0.27 | |
| Jack Sanford | 1961 | PBP | 14 | 7 | .667 | 3.22 | 38 | 27 | 11 | 6 | 1 | 0 | 0 | 204 | 95 | 106 | 1.299 | 11.69 | 0.97 | |
| Tommy John | 1977 | MWB | 18 | 9 | .667 | 3.24 | 38 | 38 | 0 | 1 | 0 | 0 | 0 | 219.2 | 61 | 132 | 1.256 | 11.31 | 0.98 | |
| Glen Hobbie | 1961 | PBP | 12 | 6 | .667 | 3.31 | 34 | 26 | 8 | 3 | 1 | 2 | 67 | 184.2 | 50 | 94 | 1.256 | 11.31 | 1.12 | |
| Gerrit Cole | 2015 | PBP | 16 | 8 | .667 | 3.60 | 30 | 30 | 0 | 1 | 1 | 0 | 0 | 207.1 | 50 | 218 | 1.158 | 10.42 | 0.74 | |
| Randy Johnson | 1997 | PBP | 16 | 8 | .667 | 3.64 | 32 | 32 | 0 | 1 | 0 | 0 | 0 | 207.2 | 103 | 304 | 1.291 | 11.61 | 1.08 | |
| John D'acquisto | 1974 | PBP | 12 | 6 | .667 | 3.74 | 26 | 26 | 0 | 0 | 0 | 0 | 0 | 149.1 | 84 | 100 | 1.353 | 12.17 | 0.96 | |
| Howard Ehmke | 1927 | IMG | 14 | 7 | .667 | 3.75 | 50 | 24 | 26 | 3 | 0 | 0 | 0 | 197 | 58 | 110 | 1.310 | 11.79 | 0.41 | |
| Don Mossi | 1961 | GTL | 14 | 7 | .667 | 3.78 | 30 | 30 | 0 | 7 | 0 | 0 | 0 | 223.2 | 56 | 126 | 1.256 | 11.31 | 1.05 | |
| Jim O'toole | 1961 | IMG | 16 | 8 | .667 | 3.83 | 35 | 29 | 6 | 7 | 2 | 2 | 100 | 213.2 | 112 | 137 | 1.395 | 12.55 | 0.67 | |
| Floyd Bannister | 1987 | SRR | 16 | 8 | .667 | 3.86 | 31 | 31 | 0 | 4 | 1 | 0 | 0 | 200.2 | 69 | 113 | 1.186 | 10.67 | 1.35 | |
| Carlos Perez | 1997 | GTL | 16 | 8 | .667 | 3.91 | 30 | 30 | 0 | 3 | 1 | 0 | 0 | 207 | 52 | 107 | 1.208 | 10.87 | 1.04 | |
| Randy Gumpert | 1949 | GTL | 16 | 8 | .667 | 3.99 | 33 | 31 | 2 | 9 | 0 | 0 | 0 | 232.1 | 67 | 68 | 1.248 | 11.23 | 0.97 | |
| Dick Ruthven | 1977 | PBP | 10 | 5 | .667 | 4.15 | 36 | 25 | 11 | 1 | 0 | 0 | 0 | 151.2 | 77 | 86 | 1.444 | 13.00 | 0.83 | |
| 58 | Red Lucas | 1927 | COL | 17 | 9 | .654 | 3.14 | 35 | 33 | 2 | 8 | 0 | 0 | 0 | 252 | 58 | 67 | 1.131 | 10.18 | 0.32 |
| Don Sutton | 1977 | THD | 17 | 9 | .654 | 4.57 | 37 | 37 | 0 | 2 | 0 | 0 | 0 | 240.1 | 88 | 162 | 1.456 | 13.11 | 1.24 | |
| 60 | Guy Bush | 1927 | IMG | 15 | 8 | .652 | 2.51 | 37 | 23 | 14 | 2 | 0 | 4 | 100 | 190 | 71 | 76 | 1.137 | 10.23 | 0.14 |
| Hank Borowy | 1949 | PVA | 15 | 8 | .652 | 3.65 | 31 | 31 | 0 | 3 | 1 | 0 | 0 | 199.2 | 94 | 55 | 1.337 | 12.04 | 0.81 | |
| 62 | Cliff Chambers | 1949 | PVA | 13 | 7 | .650 | 3.70 | 32 | 29 | 3 | 2 | 0 | 0 | 0 | 194.2 | 74 | 98 | 1.279 | 11.51 | 0.92 |
| Francisco Cordova | 1997 | THD | 13 | 7 | .650 | 4.02 | 30 | 30 | 0 | 3 | 1 | 0 | 0 | 177 | 59 | 122 | 1.299 | 11.69 | 1.02 | |
| Bob Knepper | 1977 | THD | 13 | 7 | .650 | 4.41 | 28 | 28 | 0 | 0 | 0 | 0 | 0 | 163.1 | 76 | 114 | 1.371 | 12.34 | 1.21 | |
| Ernie Broglio | 1961 | SSL | 13 | 7 | .650 | 4.47 | 35 | 23 | 12 | 2 | 0 | 0 | 0 | 173 | 88 | 107 | 1.410 | 12.69 | 1.04 | |
| Dick Fowler | 1949 | THD | 13 | 7 | .650 | 4.83 | 31 | 31 | 0 | 3 | 0 | 0 | 0 | 190 | 100 | 53 | 1.653 | 14.87 | 1.14 | |
| 67 | Dick Donovan | 1961 | MNL | 11 | 6 | .647 | 2.60 | 23 | 23 | 0 | 7 | 2 | 0 | 0 | 169.1 | 26 | 70 | 0.980 | 8.82 | 1.01 |
| Bill Werle | 1949 | COL | 11 | 6 | .647 | 2.71 | 54 | 27 | 27 | 0 | 0 | 1 | 33 | 172.2 | 47 | 87 | 1.112 | 10.01 | 0.47 | |
| 69 | Jim Clancy | 1987 | PBP | 16 | 9 | .640 | 4.35 | 33 | 33 | 0 | 3 | 0 | 0 | 0 | 223.1 | 76 | 200 | 1.401 | 12.61 | 1.05 |
| 70 | Ted Lyons | 1927 | BUM | 23 | 13 | .639 | 3.46 | 84 | 14 | 70 | 5 | 1 | 4 | 50 | 312 | 77 | 80 | 1.333 | 12.00 | 0.35 |
| 71 | Dave Koslo | 1949 | COL | 14 | 8 | .636 | 3.10 | 92 | 6 | 86 | 0 | 0 | 20 | 83 | 209 | 71 | 77 | 1.129 | 10.16 | 0.69 |
| Tom Glavine | 1997 | SRR | 14 | 8 | .636 | 3.15 | 34 | 34 | 0 | 1 | 0 | 0 | 0 | 234.1 | 80 | 146 | 1.208 | 10.87 | 0.73 | |
| Dutch Ulrich | 1927 | DIN | 14 | 8 | .636 | 3.19 | 30 | 28 | 2 | 3 | 0 | 0 | 0 | 203 | 55 | 52 | 1.330 | 11.97 | 0.49 | |
| Sheriff Blake | 1927 | PBP | 14 | 8 | .636 | 4.06 | 45 | 23 | 22 | 8 | 0 | 4 | 80 | 213 | 105 | 65 | 1.610 | 14.49 | 0.17 | |
| Bobby Witt | 1997 | MIT | 7 | 4 | .636 | 4.63 | 48 | 13 | 35 | 4 | 1 | 1 | 50 | 149.2 | 60 | 97 | 1.437 | 12.93 | 1.38 | |
| 76 | Carmen Hill | 1927 | SSL | 19 | 11 | .633 | 2.94 | 49 | 31 | 18 | 13 | 2 | 1 | 100 | 294.1 | 107 | 98 | 1.284 | 11.56 | 0.40 |
| 77 | Hector Santiago | 2015 | GTL | 12 | 7 | .632 | 2.59 | 28 | 28 | 0 | 2 | 1 | 0 | 0 | 180.2 | 64 | 151 | 1.024 | 9.22 | 0.95 |
| Shawn Estes | 1997 | IMG | 12 | 7 | .632 | 3.99 | 29 | 29 | 0 | 1 | 0 | 0 | 0 | 187.1 | 104 | 172 | 1.399 | 12.59 | 0.91 | |
| Mike Morgan | 1997 | DIN | 12 | 7 | .632 | 4.06 | 26 | 26 | 0 | 0 | 0 | 0 | 0 | 159.2 | 43 | 101 | 1.309 | 11.78 | 1.01 | |
| 80 | Gerry Staley | 1949 | COL | 17 | 10 | .630 | 3.84 | 85 | 4 | 81 | 0 | 0 | 14 | 67 | 182.2 | 67 | 57 | 1.418 | 12.76 | 0.34 |
| Bob Purkey | 1961 | GTL | 17 | 10 | .630 | 3.89 | 33 | 31 | 2 | 12 | 1 | 0 | 0 | 242.2 | 66 | 120 | 1.302 | 11.72 | 1.30 | |
| Jesse Hubbard | 1927 | GTL | 17 | 10 | .630 | 4.22 | 31 | 31 | 0 | 12 | 2 | 0 | 0 | 239 | 27 | 45 | 1.251 | 11.26 | 0.75 | |
| Joe Shaute | 1927 | MWB | 17 | 10 | .630 | 4.23 | 30 | 30 | 0 | 9 | 0 | 0 | 0 | 231.2 | 93 | 82 | 1.459 | 13.13 | 0.70 | |
| Phil Niekro | 1977 | SRR | 17 | 10 | .630 | 4.25 | 37 | 37 | 0 | 6 | 1 | 0 | 0 | 243.2 | 152 | 182 | 1.592 | 14.33 | 0.66 | |
| 85 | Jim Archer | 1961 | PBP | 15 | 9 | .625 | 2.49 | 38 | 25 | 13 | 4 | 1 | 1 | 50 | 195.1 | 59 | 108 | 1.280 | 11.52 | 0.37 |
| Jim Kaat | 1974 | IMG | 10 | 6 | .625 | 2.82 | 25 | 25 | 0 | 4 | 2 | 0 | 0 | 179 | 47 | 76 | 1.067 | 9.60 | 0.50 | |
| Howie Fox | 1949 | DIN | 15 | 9 | .625 | 3.08 | 44 | 33 | 11 | 1 | 0 | 0 | 0 | 239.2 | 81 | 82 | 1.218 | 10.97 | 0.64 | |
| Brad Radke | 1997 | GTL | 15 | 9 | .625 | 3.10 | 32 | 32 | 0 | 7 | 1 | 0 | 0 | 235.1 | 58 | 157 | 1.045 | 9.41 | 0.84 | |
| Luis Tiant | 1974 | GRR | 15 | 9 | .625 | 3.76 | 31 | 31 | 0 | 6 | 3 | 0 | 0 | 220.1 | 97 | 131 | 1.389 | 12.50 | 0.61 | |
| J.A. Happ | 2015 | COL | 15 | 9 | .625 | 4.15 | 32 | 32 | 0 | 0 | 0 | 0 | 0 | 164.2 | 63 | 131 | 1.403 | 12.63 | 1.20 | |
| Preacher Roe | 1949 | TLF | 15 | 9 | .625 | 4.57 | 30 | 30 | 0 | 6 | 1 | 0 | 0 | 222.2 | 56 | 124 | 1.397 | 12.57 | 1.21 | |
| 92 | Corner Pocket Yokely | 1927 | TLF | 18 | 11 | .621 | 3.00 | 34 | 34 | 0 | 8 | 4 | 0 | 0 | 246.1 | 86 | 71 | 1.100 | 9.90 | 0.40 |
| 93 | Bert Blyleven | 1974 | GTL | 13 | 8 | .619 | 2.45 | 27 | 27 | 0 | 13 | 1 | 0 | 0 | 213.1 | 65 | 200 | 1.144 | 10.29 | 0.38 |
| Steve Carlton | 1977 | SRR | 13 | 8 | .619 | 4.02 | 35 | 35 | 0 | 3 | 1 | 0 | 0 | 230.1 | 77 | 156 | 1.389 | 12.50 | 0.94 | |
| 95 | Ken Raffensberger | 1949 | THD | 21 | 13 | .618 | 4.05 | 41 | 40 | 1 | 12 | 4 | 0 | 0 | 277.2 | 102 | 117 | 1.401 | 12.61 | 0.88 |
| 96 | Jerry Koosman | 1977 | MNL | 16 | 10 | .615 | 2.62 | 30 | 30 | 0 | 8 | 2 | 0 | 0 | 227 | 69 | 190 | 1.167 | 10.51 | 0.95 |
| Harry Salmon | 1927 | MIT | 16 | 10 | .615 | 2.75 | 79 | 17 | 62 | 11 | 1 | 7 | 78 | 281 | 63 | 108 | 1.125 | 10.12 | 0.54 | |
| Orel Hershiser | 1987 | DPC | 16 | 10 | .615 | 3.64 | 37 | 35 | 2 | 4 | 2 | 0 | 0 | 239.2 | 69 | 191 | 1.248 | 11.23 | 0.94 | |
| 99 | Dallas Keuchel | 2015 | COL | 14 | 9 | .609 | 3.41 | 31 | 31 | 0 | 3 | 1 | 0 | 0 | 224.1 | 64 | 224 | 1.137 | 10.23 | 0.72 |
| Lefty Smith | 1949 | CIR | 14 | 9 | .609 | 3.43 | 35 | 24 | 11 | 7 | 2 | 0 | 0 | 202 | 125 | 86 | 1.391 | 12.52 | 0.53 |