Eastern Paraguay, south-eastern Brazil (southern from south-eastern Bahia and southern Espírito Santo), north-eastern Argentina (south to eastern Santa Fe, Entre Ríos and northern Buenos Aires) and Uruguay.
 
Rarity Status
Currently this species is not classified as a rarity in this country OR information has not been updated.
Population
Estimated population is unknown (2010).
Spix's Spinetail (Synallaxis spixi) [XC428014]
by Robson Silva e Silva from Trilha do Portal do C\u00e9u, Patrimonio da Penha-ES, Esp\u00edrito Santo, Brazil (canto)
Spix's Spinetail (Synallaxis spixi) [XC421882]
by Marcelo Jordani Feliti from S\u00e3o Miguel Arcanjo, S\u00e3o Paulo, Brazil (song)
Subspecies
No subspecies.
Close relationship to Pale-breasted Spinetail (Synallaxis albescens) and Dark-breasted Spinetail (Synallaxis albigularis) suggested by plumage and vocal similarities. In the past was considered conspecific with Cinereous-breasted Spinetail (Synallaxis hypospodia). The two are thought to be possibly sister-species by some authors, but others consider them not closely related because of differences in tail morphology, throat pattern and voice.