The genus Holochilus Brandt, 1835 is represented in Rio Grande do Sul, Southern Brazil, by two forms: H. brasiliensis vulpinus (Brants, 1827) e H. magnus Hershkovitz, 1955. They are myomorph rodents with semi-aquatic habits. Species of Holochilus range from Northern South America to Central Argentina. In this paper, I present an analysis of standard measurements of specimens collected in Southern Brazil and deposited in the collections of FZB, PUC and UFRGS and a distribution map with collecting localities.
