The present work summarises data on the species composition and distribution of freshwater molluscs (gastropods and bivalves) in Bulgaria. This was done on the basis of both critical surveys of publications by other scientists and the research carried out by the author in the period 1950-1999. Information about 89 species belonging to 45 genera and families is given. Of these 89 species no less than 16 can be considered as endemic to the Balkan (4) and Bulgaria (12).
For each species the bibliography, the general distribution, the distribution in Bulgaria, the ecology and remarks are given. It concludes with a checklist of localities and an index.