Bibimys is a genus of new world rats.
Presently, the distributional range of Bibimys covers Argentina, Brasil and Paraguay. As with most of the species in the South American sigmodontinae, Bibimys has been arranged as a genus based mainly on morphological differences with the other living genera. Bibimys belongs to the tribe Scapteromyini, first informally described by P. Hershkovitz in 1966 and formally introduced later by E. Massoia in 1979. The scapteromyines are a small sigmodotine tribe, consisting of the three genera: Bibimys, Kunsia and Scapteromys. Many of the species have been described from badly preserved specimens. One of the greatest challenges lying with sigmodontine systematics, is that there is much confusion and disagreement amongst authors regarding to the relationship between their tribes and their real identity is not clear. Therefore, there are some disagreement regarding even to the validity of the scapteromyines or eventually, even of Bibimys as a genus. In a recent broad phylogenetic study, Smith and Patton found that scapteromyine genera Kunsia and Scapteromys formed a clade closely related with the Akodontini. Further analysis of DNA sequences may shed new light regarding to Bibimys taxonomical position. Generic diagnosis emended, alpha taxonomy reviewed, and known fossil and recent occurrences consolidated by D’Elía et al. (in press). In a recent study, D´Elia, Pardiñas and Myers have provisionally retained three species of Bibimys, given the inadequacies of sample size and geographic representation, however, they acknowledged that morphological, karyotypic, and genetic evidence for their separation is unpersuasive.