Megaceropsis Dechambre, 1976 (Coleoptera, Melolonthidae, Dynastinae, Oryctini) is a South American genus with two known species until now: Megaceropsis quadridentata Dechambre, 1976 and Megaceropsis lecourti Dechambre, 1996. We describe a third species herein: Megaceropsis kleytoni sp. nov., from Brazil. Illustrations, a distributional map, and an identification key including all Megaceropsis species are provided. Additionally, a first record of M. quadridentata from Brazil is presented.