South-eastern Brazil (Paraná and Sío Paulo east to southern Minas Gerais and Rio de Janeiro, south to Rio Grande do Sul), adjacent eastern Paraguay, Uruguay and north-eastern Argentina (eastern from extreme eastern Santa Fe, south to northern Buenos Aires).
 
Population
Estimated population is unknown (2010).
Diademed Tanager (Stephanophorus diadematus) [XC84745]
by Jeremy Minns from Itatiaia National Park. Agulhas Negras road, Brazil (call)
Diademed Tanager (Stephanophorus diadematus) [XC47051]
by Bernabe Lopez-Lanus from Estancia El Potrero (alrededores Puerto Unzue), Gualeguaychu, Entre Rios, Argentina (song)