The Rusty-breasted Nunlet is distributed in the Amazon Basin with disjunct populations in eastern and south-eastern Brazil. It is found in the mid-storey of humid forest, gallery forest or sandy-belt forest.

It is a small, fairly drab and inconspicuous bird with a whitish band from bill to eye, a whitish eye-ring and grey-brown upperparts. Below there are rufous tinges to the breast and flanks.