(Minimum 150 innings)
* = Lowest ERA in NL/AL*1. Sandy Koufax - 1.73 in 323 innings (Los Angeles Dodgers, 1966)
*2. Sandy Koufax - 1.74 in 223 innings (Los Angeles Dodgers, 1964)*3. Sandy Koufax - 1.88 in 311 innings (Los Angeles Dodgers, 1963)
3. Joe Horlen - 1.88 in 210 innings (Chicago White Sox, 1964)
*4. Sandy Koufax - 2.04 in 335 innings (Los Angeles Dodgers, 1965)5. Joe Horlen - 2.06 in 258 innings (Chicago White Sox, 1967)
6. Dave Roberts - 2.10 in 269 innings (San Diego Padres, 1971)
7. Joe Horlen - 2.37 in 223 innings (Chicago White Sox, 1968)
8. Joe Horlen - 2.43 in 211 innings (Chicago White Sox, 1966)
9. Ken Holtzman - 2.51 in 265 innings (Oakland Athletics, 1972)*10. Sandy Koufax - 2.54 in 184 innings (Los Angeles Dodgers, 1962)
*11. Saul Rogovin - 2.78 in 216 innings (Detroit Tigers/Chicago White Sox, 1951)12. Dave Roberts - 2.85 in 249 innings (Houston Astros, 1973)
13. Joe Horlen - 2.88 in 219 innings (Chicago White Sox, 1965)
14. Ken Holtzman - 2.97 in 297 innings (Oakland Athletics, 1973)15. Ken Holtzman - 3.07 in 255 innings (Oakland Athetlics, 1974)
16. Dan Warthen - 3.11 in 167 innings (Montreal Expos, 1975)
17. Ken Holtzman - 3.14 in 266 innings (Oakland Athetlics, 1975)18. Steve Stone - 3.23 in 250 innings (Baltimore Orioles, 1980)
19. Ken Holtzman - 3.35 in 215 innings (Chicago Cubs, 1968)
20. Ken Holtzman - 3.38 in 287 innings (Chicago Cubs, 1970)21. Dave Roberts - 3.40 in 204 innings (Houston Astros, 1974)
22. Sandy Koufax - 3.52 in 255 innings (Los Angeles Dodgers, 1961)23. Ross Baumgarten - 3.54 in 190 innings (Chicago White Sox, 1979)
24. Ken Holtzman - 3.58 in 261 innings (Chicago Cubs, 1969)
25. Ken Holtzman - 3.65 in 246 innings (Baltimore Orioles/New York Yankees, 1976)26. Jason Marquis - 3.71 in 201 innings (St. Louis Cardinals, 2004)
27. Barry Latman - 3.75 in 156 innings (Chicago White Sox, 1959)28. Steve Stone - 3.77 in 186 innings (Baltimore Orioles, 1979)
29. Joe Horlen - 3.78 in 235 innings (Chicago White Sox, 1969)
30. Ken Holtzman - 3.79 in 220 innings (Chicago Cubs, 1966)31. Dave Roberts - 3.81 in 181 innings (San Diego Padres, 1970)
32. Saul Rogovin - 3.85 in 231 innings (Chicago White Sox, 1952)33. Sandy Koufax - 3.91 in 175 innings (Los Angeles Dodgers, 1960)
34. Steve Stone - 3.95 in 214 innings (Chicago Cubs, 1975)