I characterize the nest, eggs and nestlings of the Short-tailed Antthrush (Chamaeza campanisona) based on a nest found in an Atlantic semideciduous forest in southern Brazil. The nest was in a natural cavity 1.5 m above the ground and it was 87 cm deep. Three pure white eggs were recorded on a bed of leaves. The nestlings had pink skin, blackish gray down and they left the nest 16-19 days after hatching. Images from inside the nest, the eggs and nestlings are first presented, even for the genus. The Chamaeza nest type and egg coloration resemble nest describe for the family Formicariidae, supporting the separation from the family Grallariidae.