Ten species of onuphid polychaetes were identified from the sublitoral of Ubatuba, on the coast of the state of São Paulo, Brazil: Diopatra cuprea (Bosc, 1802); Diopatra tridentata Hartman, 1944; Kinhergonuphis difficilis (Fauchald, 1982); Kinhergonuphis fauchaldi Lana, 1991; Kinhergonuphis orensanzi (Fauchald, 1982); Kinhergonuphis tenuis (Hansen, 1882); Mooreonuphis nebulosa (Moore, 1911); Mooreonuphis pallidula (Hartman, 1965); Mooreonuphis intermedia (Kinberg, 1865); Onuphis dibranchiala Willey, 1905. A discussion on the characteristics of the species found and related species is also provided.

This work constitutes a systematic survey of the Annelida Polychaeta from the sublitoral of the São Paulo State coast (Ubatuba), southeast Brazil. From 105 identified species, 20 are new records for the brazilian coast. An analysis of affinity degree between the fauna of the studied region and of the adjacents biogeographic provinces shows that 25,5% of the species are endemic for the Paulista Province, 19,0% amphi-american, 17,0% cosmopolite and 16,8% amphi-atlantic. An affinity with species from the Patagonian (7,4%) and Caribbean (2,0%) Provinces is smaller than that of other authors, for the southeast Brazilian coast.

Seven species of Syllidae (Annelida, Polychaeta) inhabiting colonies of the bryozoan Schizoporella unicornis (Johnston), a common species on the beaches of Ubatuba and São Sebastião, São Paulo State, Brazil are described: Exogone occidentalis Westheide, 1974; Haplosyllis spongicola (Grube, 1855); Opistosyllis corallicola Hartmann-Schröder, 1965; Syllis gracilis (Grube, 1840); Trypanosyllis taeniaformis (Haswell, 1866); Typosyllis maculata Imajima, 1966 and Typosyllis variegata (Grube, 1860). Among these, E. occidentalis, O. corallicola, T. taeniaformis and T. maculata are cited for the first time for the Brazilian coast. The most abundant of these species was S. gracilis.

Three species of the family Phyllodocidae and two of Hesionidae were found in colonies of the bryozoan Schizoporella unicornis (Johnston) on the beaches of Ubatuba and São Sebastião, São Paulo State, Brazil. Among these, Eumida sanguinea (Phyllodocidae) is registered for the first time on the Brazilian coast. Among the other species Ophiodromus pugettensis (Hesionidae) was one of the most abundant polychaetous annelids of the bryzoan fauna.