The genus Ictalurus is represented in northwest Mexico by a taxonomically problematic group of populations informally treated as the Ictalurus pricei complex. Several morphological characters separate the undescribed catfish populations (Sinaloa catfish) in the Culiacan River and San Lorenzo River basins from the Yaqui catfish (Ictalurus pricei), the only catfish species described from the region. In this paper, a phylogenetic analysis of cytochrome oxidase subunit 1 supports the monophyly of the I. pricei complex (Yaqui and Sinaloa catfishes). The complex appears closely related to Ictalurus lupus, another species from the American Southwest.