The Black-cheeked Ant Tanager (Habia atrimaxillaris) is endemic to the Osa Peninsula on the south Pacific coast of Costa Rica. There is little knowledge of the natural history and especially the reproductive habits of this species. We describe the nest and eggs of the Black-cheeked Ant Tanager based on observations of three nests near Puerto Jiménez, Puntarenas, Costa Rica. The nests and eggs were similar to other species of Habia supporting previous work suggesting relationships within Habia.