This annotated list of the fishes of Lake Ontario and its watershed is based on published distribution records, museum collections, and reports of fish surveys that confirm the occurrence of fish species dating back to the 1850's. It includes 130 forms (129 spp. + the hybrid splake), 20 of which have disappeared or are extremely rare today. Considering species present only in the lake proper, 64 were reported in 1929, and 51 of those remained in 1972-73 (13 having disappeared). Seventeen species and the splake are fishes not known to have occurred in the lake in 1929 or were introduced since then. A list of 86 references pertinent to the study of the fish fauna of the watershed is given. The present list, started in 1972, includes some information from as late as 1976.