Abstract A total of 1,294 goodeid fish representing 35 species collected from 51 localities in Mexico was examined for adult intestinal helminths. Sampling was conducted between September 2001 and December 2004. Ten helminth species were collected (4 digeneans, 2 cestodes, and 4 nematodes). Allocreadium lobatum and Proteocephalus longicollis are reported for the first time in Mexico. The geographic and host range of Allocreadium mexicanum is extended to include new host species within Goodeinae in the Mezquital basin. Margotrema bravoae was found mainly in the Lerma-Santiago River basin and sparsely in the Balsas River, and Margotrema guillerminae was only found in the Western basins related to the Mesa Central. Proteocephalus longicollis was found in 1 host and 1 location. Rhabdochona lichtenfelsi was the most prevalent and abundant helminth in collections from the freshwater basins of Lerma-Santiago and Panuco river systems. It is considered as the only nematode species of goodeids endemic to both basin...