Capitellids of the genus Scyphoproctus are most readily identified by the distinctive pygidial region, generally consisting of a number of segments fused with the pygidium, forming a weakly or well-developed anal plaque. To date, there are 17 valid species, however, only one species has been previously recorded in Brazil. The aim of this study was to investigate the diversity of the genus occurring along the Northeast and Southeast coasts and sublittoral areas of Brazil. Three new species have been found in samples collected in a variety of habitats and depths, Scyphoproctus paivai sp. nov., S. profundus sp. nov., and S. robustus sp. nov. The new species are herein described and compared to other species of the genus and type material of two additional species are re-described, Scyphoproctus oculatus Reish, 1959 and S. pseudoarmatus (Silva 1965). The genus Heteromastides Augener, 1914 is herein relocated in Scyphoproctus Gravier, 1904 and the previous species Heteromastides platyproctus Pillai, 1961 (junior homonym) renamed as Scyphoproctus telesphorei n. nov. after the species author Telesphore Gottfried Pillai, because there is already a species named Scyphoproctus platyproctus Jones, 1961 (senior homonym). A taxonomic key of the valid and new species is also given.