Eastern and south-eastern Brazil in interior southern Bahía, western Espírito Santo and southern Minas Gerais south to Rio Grande do Sul, and north-eastern Argentina (Misiones). Sight records from south-eastern Paraguay (Caazapá) require confirmation.
 
Population
Estimated population is unknown (2010).
Mouse-colored Tapaculo (Scytalopus) [XC8458]
by Ricardo Gagliardi from Taquaril - Petr\u00f3polis - RJ, Brazil (call)
Mouse-colored Tapaculo (Scytalopus) [XC75542]
by Jeremy Minns from Parque Estadual Intervales, SP, Brazil (song)
Subspecies
No subspecies.
Closely related to Marsh Tapaculo (Scytalopus iraiensis). Some geographical variation in voice suggests that present species may involve more than a single taxon. Birds from north-eastern Argentina (Misiones) have longest bill and shortest wing, but no other differences sufficient to warrant subspecific separation.