The chestnut-capped brushfinch is a large, robust, mainly terrestrial species, 19 cm long and weighing 45 g. It has a long slender bill and large feet and legs. The adult has a distinctive head pattern, with a yellow-edged chestnut crown and nape, black forehead and head sides, white spots in the centre and each side of the forehead, and a white throat which is often puffed up when the bird is excited. The upperparts are dark olive, with darker wings. The white central breast is separated from the white throat by a black band. The breast sides are grey, and the flanks and lower belly are olive-green. Young birds have a sooty-brown cap, sooty face and olive-brown upperparts, throat and breast.