Shell-abounding thanatocenoses were collected from recent sediments of the Vistula River near Cracow formed during a few flood episodes. They are composed of 65 species of aquatic and terrestrial molluscs. Considerable differences between particular mollusc assemblages deposited on the river banks are controlled by both the intensity of flood and the changes of the fauna inhabiting the catchment area, mainly the floodplain and the river itself. Living specimens and empty shells of Potamopyrgus antipodarum (Gray) were found for the first time in thanatocenoses accumulated in Tyniec in 1999 and 2000.