Avian bamboo specialists are an ecologically distinctive group of birds in the Neotropics with some seedeater species having nomadic movements following bamboo (Guadua, Chusquea or Rhipidocladum) mast seeding. We reviewed the range and seasonal distribution of Blackish-blue Seedeaters (Amaurospiza moesta) using published and unpublished records, museum specimens, sound libraries, and intensive field work. We report the first occurrence of Blackish-blue Seedeaters in the Brazilian State of Mato Grosso, a male collected in Fazenda Baía de Pedra, Cáceres (16° 27′ 29″ S, 58° 09′ 59″ W). We also recorded this species in two localities in the Cerrado region (a tropical savannah) of Minas Gerais: the Santo Antonio River, Presidente Olegário (18° 07′ 48″ S, 46° 11′ 57″ W), and the Abaeté River, São Gonçalo do Abaeté (18° 05′ S, 45° 22′ W). These records represent a remarkable range extension, demonstrating this species is distributed across the Cerrado. We found no evidence of regular large scale or local movements of this species, which seems to be resident, at least in Argentina, which had the largest data set.