Eastern and south-eastern Brazil (Alagoas; central Mato Grosso and southern Bahia south to Santa Catarina), adjacent eastern Paraguay and north-eastern Argentina (Misiones).
 
Population
Estimated population is unknown (2010).
Chestnut-bellied Euphonia (Euphonia pectoralis) [XC753640]
by Mateus Gon\u00e7alves Santos from S\u00e3o Sebasti\u00e3o, Praia da Jur\u00e9ia S\u00e3o Paulo-SP Brasil, Brazil (song)
Chestnut-bellied Euphonia (Euphonia pectoralis) [XC504963]
by Dante Buzzetti from Serra do Ouro, Esta\u00e7\u00e3o Ecol\u00f3gica de Murici, Murici, Alagoas, Brazil (call)
Subspecies
Recent molecular-genetic analysis indicates that genus belongs in family Fringillidae. May form a superspecies with Rufous-bellied Euphonia (Euphonia rufiventris) and Golden-sided Euphonia (Euphonia cayennensis). Described taxon Euphonia vittata believed to have been a hybrid between present species and Orange-bellied Euphonia (Euphonia xanthogaster).