The Plumbeous Seedeater is a small bird about 10.5–11 cm long. In lowland Bolivia it is recorded in wooded grassland and savanna; in Colombia, records include the eastern plains and parts of the Andes.
The male is gray overall, with a white malar spot and a blackish bill. The female is brownish, but the Bolivia account cautions that she may not be safely identifiable.
It uses wooded grassland and seasonally flooded savanna, foraging on the ground for seeds and insects. It occurs alone, in pairs or flocks; males sing from bushes and termite mounds.
An extinction-risk assessment has not been added yet.