Sinaloa is a Mexican state located in the Southeastern Gulf of California, represented by a wide macroinvertebrates
biodiversity, including polychaetes. This group is highly diverse in the state, nevertheless, the information on the species’ records are
scattered in numerous sources. There is a high presence of supposed cosmopolitan polychaetes in the Eastern Tropical Pacific (ETP),
therefore it is expected that numerous species are questionable to Sinaloa. The purpose of this study was to compile the name of all
polychaete species currently registered in Sinaloa, including the bathymetric distribution and an assessment of their biogeographic
distribution in the zoogeographic region ETP. We conducted a broad literature search to compile records of polychaete species dated
until 2014. The bathymetric distribution in the state and the type locality of the species is given. The literature review of 78 references
revealed that 17 orders, 52 families, 217 genera and 464 species of polychaetes are in Sinaloa. Phyllodocida, Eunicida, Sabellida,
Spionida, Cirratulida and Terebellida were the most representative orders, while Spionidae, Nereididae, Eunicidae, Lumbrineridae,
Onuphidae and Phyllodocidae were to the families; Eunice (Eunicidae), Scoletoma (Lumbrineridae) and Aricidea (Paraoindiae) were
to the genera. Sinaloa has one of the highest numbers of polychaete species in Mexico; however, more than 70% are questionable
species in the region. All the exotic polychaete species recorded in the Mexican Pacific are in Sinaloa. More polychaete species were
recorded in the upper layer over the oxygen minimum zone (OMZ) than in the lower. The discontinuous distribution of species in
common of both layers is questionable; any species has been recorded in the OMZ of Sinaloa. OMZ represents a physiological barrier
to upward migration of species in the water column.