Background. The Cortez Province (CP) is located in the transitional warm-temperate/subtropical region that allows the ichthyological component inhabiting it to be a mixture of elements of different biogeographic affinities. Since the first systematic analysis of the fish fauna of the Gulf of California in the 1960’s a major portion of the endemic species was recognized. Subsequently, a total of 31 new endemic species have been described in the CP. This study constitutes an amendment of the fish component of the CP, including the most relevant ecological attributes of the species, along with an updated taxonomic list. Materials and Methods. A comprehensive literature review was made, considering current biological knowledge, and taxonomic status of the endemic species from the CP. Those fish species with restricted distribution ranges, falling within the limits of this province, were considered endemic. Additionally, and to recognize the dominant ecological attributes of the CP endemic species, the preferential habitat, bathymetric distribution, the reproduction strategy, and the maximum total length (TL) were recorded. Results. Seventy-nine endemic species were recognized and grouped in 13 orders, 29 families, and 59 genera. Gobiidae (12), Chaenopsidae (8), and Labrisomidae (7) are the families with the highest species richness, and Sebastes (6 species), the most diverse genus. Forty-five percent of the species are associated with coral and rocky reefs, with 35% distributed within the first 10 m depth layer. The dominant reproduction strategies are: oviparous with benthic eggs and pelagic larval phase (48.7%), and oviparous with pelagic eggs (25.6%). More than half of the species (52%) are shorter than 10 cm (total length). Conclusion. The list of endemic species presented in this study is not conclusive, still undescribed species have not been included, detected differences (morphologic and/or genetic) in several species with disjunct populations may increase the diversity of this province.