The main objective of this study was to determine the diversity and community structure of freshwater molluscs of the upper course of the Sava river. Field research was conducted during June and September 2012 at 16 stations distributed along the upper course of the river. Snails are determined to species level and bivalves to genus level. During this study, a total of 14 snail species and one bivalve genus were found. The highest number of species, five, were recorded at station S-Med. The most common species of snails are Ancylus fluviatilis and Sadleriana fluminensis. Analysis of molluscs size classes showed that younger individuals are also present at investigated stations. Analysis of molluscs functional feeding guilds showed that dominated group is grazers followed by detritivors unless the last two stations were dominated gruop is active filtrators. Highest values of the Shannon and Simpson diversity indices were recorded at stations S-Lju and S-Pas, while the lowest values of the indices were determined at station SD-Šob. Results of the cluster analysis showed a clear separation of the snail communities at station S-Vrh and snail communities at other stations. Finally, results of this study represent a significant contribution to the knowledge of malacofauna of the upper course of the Sava River and will be a starting point for future research.