The Lužnice River and its floodplain are protected in the Horní Lužnice Nature Reserve (Southern Bohemia, Czech Republic). The floodplain has a relatively natural character. Altogether 21 aquatic mollusc species were found at 40 sites. Lymnaea stagnalis, Physa fontinalis, Segmentina nitida and Planorbarius corneus belonged among the most often recorded species. Endangered Pisidium globulare was found. Non-native molluscs were not recorded. Only minimal changes were documented after the first research of this reserve, which was done more than 10 years ago.