A detailed malacological investigation of the territory of the Labe river floodplain near Přelouč town, which is expected to be affected by construction of a new river lock in future, was carried out in 2000. In the area under study, 22 terrestrial and 26 freshwater species have been recorded for the present. The pill clams Pisidium pseudosphaerium, P. moitessierianum, and P. hibernicum have been found there as the rarest and most endangered species.