Twenty species of Heteroptera belonging to seven families are recorded for the first time for Argentina: Ceratocombidae (1 sp.), Reduviidae (1 sp.), Miridae (4 sp.), Nabidae (5 sp.), Largidae (2 sp.), Rhyparochromidae (4 sp.), Berytidae (1 sp.), Colobathristidae (1 sp.) and Pachygronthidae (1 sp.)