In this identification guide we describe 68 species of marine sponges (Phylum Porifera, Classes Calcarea and Demospongiae) from Potiguar Basin, in the continental shelf off the Northern coast of Rio Grande do Norte State, Brazil. The descriptions contain data on the morphology, ecology and distribution of the species, and are illustrated by color photographs of live, recently collected or preserved specimens, light micrographs of the spicules and skeletal arrangement, and scanning electron micrographs of microscleres. A glossary and an identification key were included to allow the identification by non-specialists such as marine biologists, chemists, ecologists and laypersons. Out of the 68 species, 62 belong to the Class Demospongiae and 6 to the Calcarea. Ten species are new records for Brazil and 31 are new records for Rio Grande do Norte State. This work contributes to the understanding of the ecological and economic importance of the Porifera as a potential renewable resource in Brazil and to a better characterization of the benthic biota of Potiguar Basin.