South-eastern Peru (Madre de Dios), northern and eastern Bolivia, adjacent south-western Brazil (north to Rondônia), northern Paraguay, and north-western Argentina (Salta, Jujuy). Breeding range uncertain, probably only non-breeding visitor in Peru, northern Bolivia and Brazil; specimen dates indicate possible breeding as far northern as Beni (Bolivia).
 
Population
Estimated population is unknown (2010).
Plain Inezia (Inezia inornata) [XC61009]
by Bernabe Lopez-Lanus from Blanquillo Area, Madre de Dios, Peru (call?)
Plain Inezia (Inezia inornata) [XC461401]
by Dante Buzzetti from Miranda, Mato Grosso do Sul, Brazil (song)
Subspecies
No subspecies.
Genus as currently constituted is probably polyphyletic. Present species was for long placed in genus Serpophaga, and has been proposed that the two genera be merged. However, syringeal evidence suggests that Inezia is closer to Sublegatus.