Aquatic molluscs of the Dolnomoravský úval lowland (S Moravia) were investigated in 1996 and 1997. Altogether 53 aquatic species were found at 165 localities under study. Populations of very rare and endangered molluscs - Theodoxus danubialis, Viviparus acerosus, Lithoglyphus naticoides, Bithynia leachii, Anisus vorticulus, Unio crassus, Pseudanodonta complanata, Sphaerium rivicola, Pisidium moitessierianum were found.