Three new species of the South American genus Stenocrates Burmeister, 1847 (Coleoptera: Scarabaeidae: Dynastinae: Cyclocephalini) are described: Stenocrates serendipitus Ratcliffe, new species and Stenocrates mimeomus Ratcliffe, new species, both from Amazonian Peru, and Stenocrates hastatus Ratcliffe, new species from southeastern Brazil. Descriptions, diagnoses, distributions, and illustrations of the parameres of the new species are provided. Stenocrates inpai Ratcliffe, 1978, is placed in new junior synonymy with Stenocrates popei Endrödi, 1971, based upon the examination of additional specimens. A revised, annotated catalog of Stenocrates species is provided.