A survey of the the Family Gerridae was made at the Hidrological Basin of the Trombetas river, Pará state, Brazil, since the Headwaters until the Lower Trombetas river. Gerridae was the most representative Family among the aquatic Heteroptera and Gerrinae the most collected subfamily on 12 of the 35 collected points. Maps with the first geographic distributional records for the Trombetas river Basin and a key for the identification of the 5 genera and 6 species is presented.
Insecta; Hemiptera; Gerridae; Aquatic Insects