ABSTRACT: A four-year survey for Notonectidae (Insecta: Hemiptera: Heteroptera: Nepomorpha) was conducted in eleven conservation units and adjacent areas distributed over six states in northeastern Brazil. Nearly 1400 specimens of the following 18 species, four genera, and two subfamilies have been collected: Buenoaamnigenus (White, 1879), B.femoralis (Fieber, 1851), B.fuscipennis (Berg, 1879), B.koina Nieser & Pelli, 1994, B.konta Nieser & Pelli, 1994, B.mutabilis Truxal, 1953, B.pallipes (Fabricius, 1803), B.platycnemis (Fieber, 1851), B.pseudomutabilis Barbosa, Ribeiro & Nessimian, 2010, B.salutis Kirkaldy, 1904, B.tarsalis Truxal, 1953, B.unguis Truxal, 1953 (Anisopinae); Enitharoidesbrasiliensis (Spinola,
