We describe two new species of lizards of the genus Liolaemus from western Argentina. Both species belong to the petrophilus group and are easily distinguished from other members by a combination of chromatic and squamation characters. We used sequences of the mitochondrial cyt–b, 12S, and ND4 and the nuclear C–mos genes to infer the phylogeny of described species of the group. We found evidence for a monophyletic petrophilus group within the L. elongatus–kriegi complex. The petrophilus group includes Liolaemus petrophilus and two strongly supported clades, one containing the species distributed in the north, which includes one of the new species, L. talampaya; the second clade includes the species distributed in the south, including the new species, L. gununakuna.