A new species of rodent, Voalavo antsahabensis, from the eastern montane forest of Madagascar, is described from material obtained in the Anjozorobe region of the Central Highlands. The genus Voalavo was previously only known from the mountains of Anjanaharibe-Sud and Marojejy in the Northern Highlands. Several morphological, cranial, and dental characters separate V. antsahabensis from the only other named species in the genus, V. gymnocaudus. The recent discovery of this new taxon, after many years of survey work in the Anjozorobe Forest, has important implications for interpreting estimates of small mammal species richness and biogeographic patterns based on rapid inventories.