Paraguay, situated in south-central South America, lies at the nexus of several major biomes, and exhibits high species richness for a relatively small country. Nevertheless, that faunal diversity is poorly known, and new species for the country continue to come to light. This paper reports on 3 species of rodents, 1 new for the country and 2 known previously in Paraguay from 1 specimen. We emphasize the need for more and better training of new field and museum biologists, as well as for directors of permitting agencies and protected areas.