Qualitative samples of ‘opisthobranchs’ were collected from different beaches and estuaries in Ceará State, North-east Brazil. Further species distributions from the literature were used to infer patterns of distribution and to analyse faunal similarity among Atlantic biogeographic areas, Brazilian zones and the Ceará State. A total of 35 new records are reported for the Ceará State, including 19 new records from the North-east Brazilian Shelf (NBS), 12 new from the Brazilian Province and two new records from the South Atlantic. More than half of the species in this area are common between the Caribbean and Brazilian provinces, which demonstrates their capacity for crossing the Amazon–Orinoco barrier. The high percentage of occurrence in the NBS and the South Brazilian Bight, when compared to neighbouring zones, may be attributed to the poor knowledge of the Brazilian ‘opisthobranch’ fauna.
