Career
Single Season
Tim Burke                  2.61
Jeff Reardon               2.84
Ken Hill                   3.04
Pedro Martinez             3.06
Dennis Martinez            3.06
Dan Schatzeder             3.09
Mel Rojas                  3.11
Steve Rogers               3.17
Jeff Fassero               3.20
Woodie Fryman              3.24
Pedro Martinez             1.90
Dennis Martinez            2.39
Mark Langston              2.39
Steve Rogers               2.40
Pascual Perez              2.44
Steve Rogers               2.47
Dennis Martinez            2.47
Mike Marshall              2.66
Ken Hill                   2.68
Dennis Martinez            2.72
Expos ERA Leaders (min innings career 500, season 162)