During 1973-1976, 833 isolations of salmonellae were made from the aquatic biosphere of the Wabash River, Lafayette, Ind. Of the isolants, 643 were definitively serotyped. Salmonella typhimurium represented 34.4% of the cultures. Salmonella eimsbuettel previously had not been recognized in Indiana. A total of 35 serotypes and 1 untypable group C1 was obtained from the aquatic samples, ie, river water, river bottom sediment, fish, and mussels. Most of the isolants were presumed to be of human origin, because many samplings were made in close proximity to sewage treatment plant outfalls. During the survey period, epidemic salmonellosis had not been reported for the Lafayette-West Lafayette metropolitan area.