The Chestnut Munia is 11–12 cm in length. The adult has a stubby pale grey-blue bill, black head, and brown body, with a brick red patch on the lower back, visible only when it flies. Some races also have a black belly.
The sexes are similar, but immature birds have uniform pale brown upperparts, lack the dark head and have white to pale buff underparts.
The Chestnut Munia is a small gregarious bird which feeds mainly on grain and other seeds. It frequents open grassland and cultivation. The nest is a large domed grass structure in a bush or tall grass into which 4-7 white eggs are laid.