Research of freshwater Mollusca in Wonogiri was conducted in November 2010 in six rivers which estuary in Gajah Mungkur Dam. The Mollusca specimens was collected from Keduang river, Tirtomoyo river, Temon river, Solo Hulu river, Ngunggahan river and Wuryantoro river. A kuadrat transect method was used from area which have 1 kilometer in distance from estuary. The kuadrat transect was systematically located every 1 kilometer in 3 sampling sites. The specimens categorized in 13 spesies and there are one spesies have dominated in each river. The distribution of Mollusca in Solo Hulu and Ngunggahan river were random, whereas in Keduang, Tirtomoyo, Temon and Wuryantoro river were clumped. Mollusca commonly found in river which have mud substrate. The highest diversity index found in Ngunggahan river and the lowest was found in Wuryantoro river.