This poorly known antbird is endemic to upper Amazonia. Slate-colored Antbird is found in the understory of lowland evergreen forest, below 400 m, from southernmost Colombia south to northeastern Peru, and east to western Brazil. It appears to be restricted to dense terra firme forest, and does not tolerate logged areas, but so little has been published concerning its requirements that this is still open to refinement. Males are very similar to males of Spot-winged Antbird (Schistocichla leucostigma), and the two species are best separated by females, or by voice. Slate-colored Antbirds usually are found alone or in pairs, moving on or very low above the ground, foraging for insects and probably other invertebrate prey, including by flicking over leaves to expose the ground below, but also by making short sallies. Slate-colored Antbird does not seem to join mixed species flocks.