A malacological survey was carried out at the Soledade Lake, in Ouro Branco, State of Minas Gerais, for the period 1986-1991. A total amount of 46,579 mollusks was collected, and among them seven species corresponding to five families could be found, as follows: 39,176 specimens of Biomphalaria tenagophila; 1,296 B. glabrata; 7 Drepanotrema cimex; 2,527 Physa sp; 417 Lymnaea sp; 92 Pomacea hastrum, and 3,064 specimens of Melanoides tuberculata (Melanniidae = Thiaridae) were collected from March/1990 onwards. Four specimens of B. tenagophila were found to be positive for Schistosoma mansoni.