South-eastern Brazil (southern from southern Goiás, southern Minas Gerais and southern Espírito Santo), eastern Paraguay (eastern from Paraguarí), north-eastern Argentina (Misiones, eastern Corrientes) and northern Uruguay.
 
Population
Estimated population is unknown (2010).
Grey-bellied Spinetail (Synallaxis cinerascens) [XC550482]
by GABRIEL LEITE from Forestal Belga (Cruce Caballero), San Pedro, Misiones, Argentina (song)
Grey-bellied Spinetail (Synallaxis cinerascens) [XC302129]
by Jerome Fischer from Rio Piracicaba, Minas Gerais, Brazil (alarm call, song)