We examined Characodon audax (n  =  30) and C. lateralis (n  =  27) (Pisces: Goodeidae), endemic freshwater fishes from Durango, Mexico. We recorded 8 helminth species, and metacercariae of Posthodiplostomum minimum had the highest prevalence and highest mean intensity of infection. Specialist species included Salsuginus sp. (an undescribed monogenean) and the intestinal trematode Margotrema bravoae. These 3 species and larvae of the nematode Spiroxys sp. were the most frequent and abundant species. The remaining species were rare and found at low mean intensities. Intestinal helminth communities were comprised primarily M. bravoae, though most host intestines were free of macroscopic parasites. These data confirm the depauperate nature of the helminth communities of Goodeidae fish species in Nearctic Mexico. Helminth host specificity is suggested as an important factor for explaining the observed richness, and host feeding habits and local habitat characteristics are suggested as the main factors contributing to the variability observed in community composition and richness.