Fine-barred Piculet is resident in southeastern Peru and in adjacent far western Brazil. Most localities in Peru are near the base of the Andes, from the upper Ucayali valley (Santa Rosa, department to Ucayali) south and east to the department of Puno (Candamo).
Recently recorded as well in western Brazil in Acre, at several sites within the drainage of the Rio Purus (Rego et al. 2009); presumably the distribution is continuous between the Peruvian and Brazilian localities, although the species was not encountered at Balta, in Peru in the upper Purus drainage (O'Neill 1974).
The elevational distribution extends up to 1100 m (Walker et al. 2006, Schulenberg et al. 2007).