The chestnut-belted gnateater was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[2] Gmelin based his description on "Le fourmilier à oreilles blanches" that had been described and illustrated in 1778 by French polymath Comte de Buffon in his Histoire Naturelle des Oiseaux.

[9] Four subspecies are recognised:[6] It is a small dark bird with a relatively stout bill, brown upperparts and crown (the latter often tinged rufous), a white supercilium, and pinkish-grey legs.

The following range limits are: it covers the entire downstream half of the regions in the south Basin and does not extend into Bolivia.

The limits in the west are eastern and northeastern Peru with parts of northeast Ecuador and southern Colombia; the limit in this area in the west and northwest is the Rio Negro and the species is not found in the north central Amazon Basin of most of Brazil's Roraima state.