The account which follows is an up-to-date taxonomic list of gastropods occurring in the waters of the Great Lakes, with those literature citations which we consider generally reliable on these snails’ distributions among the Lakes, information on the snails’ habitats, and notes supplementing the text. Some taxonomic problems still need to be resolved, and much more information is needed on the snails’ ecology, ecological physiology, and responses to human-modifed environments. But more detail on these aspects must await further studies.