© 2018 Universidad Nacional Autonoma de Mexico. All rights reserved. In this study, a checklist of the helminth parasites of freshwater fishes from Tehuacán-Cuicatlán Biosphere Reserve in the area of Oaxaca is presented. From October to November 2015, 235 fish of 13 species were analysed from 21 localities. A total of 1,466 worms of 16 helminth taxa were recorded: 6 trematodes (3 adults and 3 metacercariae), 4 monogeneans, 1 adult cestode and 5 nematodes (4 adults and 1 larva). The helminth species Pseudoparacreptotrema macroacetabulata, Schyzocotyle acheilognathi, and Rhabdochona kidderi kidderi reached the highest prevalence (100%) in at least 1 site; Rhabdochona kidderi kidderi showed the highest abundance (34±0), while Urocleidoides simonae presented the highest average intensity (116 ± 0). The species richness showed low values compared with previous studies in the Papaloapan River; the fish Vieja fenestrata had the highest helminth species richness (5). Most helminth records presented here are new to Tehuacán-Cuicatlán Biosphere Reserve, Oaxaca region. The data generated in this study will be useful in ecological, host-parasites relationship, biogeographic and conservation studies in the Tehuacán-Cuicatlán Biosphere Reserve in the area of Oaxaca.