The present paper provides diagnostic characters from external morphology and osteology that reinforce the specific recognition of the frog Odontophrynus barrioi, describes its advertisement and encounter calls, and extends its distribution range. Odontophrynus barrioi is distinguished from all other species of the genus principally by the large size of adults, great number of irregularly arranged postorbital and temporal glands, lack of both a light vertebral line and keratinous spines, alary process of the premaxilla short and wide, pterygoid process of the maxilla well developed, and high preorbital process of the maxilla. The advertisement call consists of a trill of a single repeated and pulsed note with a low dominant frequency. The encounter call consists of only one note of similar frequency as the advertisement call, but longer in time duration. We report new records of O. barrioi from Catamarca, La Rioja, and San Juan Provinces (Argentina), that increase considerably the range of this previously poorly known species.