Introduction: This paper presents the results of an extensive survey of freshwater mollusks in the Simplício Queda Única Hydroelectric Development area, Southeast Brazil. Methods: Mollusks were collected between 2008 and 2013. All specimens were examined for the presence of larval trematodes. Results: In total, 12,507 specimens classified into 16 genera were obtained. Known snail vectors of schistosomiasis and fascioliasis and exotic species were identified, and new records are reported. Conclusions: No specimens parasitized by larval trematodes of medical interest were detected. However, the results reinforce the importance of surveillance in study areas vulnerable to the occurrence of schistosomiasis transmission.