The Patagonian extra-andean species of the genus Telmatobius are revised and discussed. The patagonicus group includes some intra-popuJatioual forms (« aquatic» and «littoral » forms), but their taxo-genetic position is still uncertain. The praebasalticus group is at present composed by four subspecies from Neuquén: praebasalticus praebasalticus from Laguna Blanca and neighbouring lagoons ; p. agilis from the Meseta of Casa de Piedra ; p. luisi from laguna Overa, Catán Lil and p. dobeslawi from the basaltic highland of Barda Santo Tomás. Moreover a very related species, T. solitarias has been described from Western Rio Negro (Las Bayas volcanic creeks). Other groups are stressed by T. reverberii and T. somuncurevsis both from the Somuncurá plateau, Rio Negro. All the extra-andean Patagonian Telinatobiid irogs were found in volcanic territories related to the ancient Tertiary activity. They live in the closed hydrological basins, typical of some basaltic landscapes. A complete serological study of the general inter-specific and populational relationships of the above mentioned forms supports the taxonomic arrangement here proposed.