The Itupararanga Reservoir is located at the Sorocaba River Basin, state of São Paulo, Brazil. Five cities use the waters of this reservoir for human consumption. Despite this intensive use of the water resource, no study has been undertaken, to investigate the ichthyofauna of this reservoir. Overall, 22 species of fishes were sampled, including 7 orders and 12 families. Characiformes and Siluriformes were the most representative with respectively 9 and 5 species. Among the families, Characidae and Pimelodidade are noticed, both with respectively 5 and 3 collected species.