Large fossil martens from Pleistocene and early-Holocene cave deposits in western North America have been assigned to the supposedly extinct species Martes nobilis. We examined quantitative differences between these fossils and the North American pine marten (M. americana), which comprises two distinctive subspecies groups. We found that the fossils are indistinguishable from the modern M. caurina subspecies group except for size. The proportions of molars are like those of the modern species, and proportions of humeri are closer to the M. caurina subspecies group than to the M. americana subspecies group. We, therefore, synonymize M. nobilis with M. americana.