We conducted the first formal quantitative study of the herpetofauna of the Jasper-Pulaski, Willow Slough and LaSalle Fish and Wildlife areas (FWA) in northwest Indiana from 1994–1996 to gather baseline data necessary to determine distribution and status of species and to monitor long-term population trends. We compared our results with those of earlier collectors Chapman Grant, Paul Swanson and Sherman Minton. A total of 339 populations of 13 amphibian species and 78 populations of 22 reptile species were encountered from 1994–1996. Only 9 species were found at all three FWAs and only 11 were commonly encountered. Sixteen new site records and new county records were made while at least 7 species with validated records before 1972 were not found during this survey and may be locally extirpated. The relative abundance of species at Jasper-Pulaski FWA has changed between the 1930s and 1990s with declines of the thirteen most abundant species and increases in some formerly overlooked or rare species. Large-scale changes in habitat may be partly responsible for changes in species abundance. All of the state-listed species (Acris crepitans blanchardi, Rana blairi, R. pipiens, Thamnophis p. proximus, Clemmys guttata, Emydoidea blandingii, Kinosternon s. subrubrum, Terrapene o. ornata, Opheodrys vernalis and Sistrurus c. catenatus), except Ambystoma laterale, have clearly declined.