Melanophryniscus pachyrhynus (Miranda-Ribeiro, 1920) was known from only two syntypes collected in southern Brazil about 100 years ago. Recently, we discovered many specimens from several localities in Brazil, and specimens were also reported for Uruguay. The Brazilian specimens were found during field trips or were stored in collections under incorrect names. Based on analysis of live specimens and freshly collected material we report that M. pachyrhynus is a relatively common species in southern Brazil, extend its geographic distribution, and add information to the species redescription.