Within the leptodactylid frog genus Physalaemus, four species comprise a monophyletic group: P. petersi (with P.freibergi designated as a junior synonym), P. pustulatus, P. pustulosus and P. coloradorum, a new species from the Pacific lowlands of Ecuador. Physalaemus petersi and P. pustulosus seem to be sister- species, as do P. pustulatus and P. coloradorum. The monophyly of the genus Physalaemus is questionable. THE 33 nominal species of small toad-like leptodactylids of the genus Physalaemus were placed in four species groups by Lynch (1970). Four species were recognized in the Physalaemus pustulosus group-P. freibergi in Bo- livia, P. petersi in the Amazon basin, P. pustulatus on the Pacific lowlands of Ecuador and P. pus- tulosus in Mexico, Central America, and north- ern South America. Lynch (1970) suggested that the nominal species P. paraensis and P. schereri were synonyms of P. petersi and that P. stentor was a synonym of P. pustulosus, although he pro- vided no evidence to support these conclusions. While studying specimens of Physalaemus that we collected on the Pacific lowlands of Peru and Ecuador, we discovered that two distinct taxa occurred in that region. Comparisons of the trans-Andean specimens with members of the P. pustulosus group from elsewhere in the range of the group resulted in this review. Our pur- poses are to: 1) define the Physalaemus pustulosus THE 33 nominal species of small toad-like leptodactylids of the genus Physalaemus were placed in four species groups by Lynch (1970). Four species were recognized in the Physalaemus pustulosus group-P. freibergi in Bo- livia, P. petersi in the Amazon basin, P. pustulatus on the Pacific lowlands of Ecuador and P. pus- tulosus in Mexico, Central America, and north- ern South America. Lynch (1970) suggested that the nominal species P. paraensis and P. schereri were synonyms of P. petersi and that P. stentor was a synonym of P. pustulosus, although he pro- vided no evidence to support these conclusions. While studying specimens of Physalaemus that we collected on the Pacific lowlands of Peru and Ecuador, we discovered that two distinct taxa occurred in that region. Comparisons of the trans-Andean specimens with members of the P. pustulosus group from elsewhere in the range of the group resulted in this review. Our pur- poses are to: 1) define the Physalaemus pustulosus