The Lacandona rainforest represents one of the most diverse Mexican tropical wet forests. Although some studies have described the amphibians and reptiles of the region, most herpetological lists come from the northern part of the Lacandona, and there are no confirmed records for many of the expected species. We reviewed databases of scientific collections, taxonomy, and published herpetological lists to produce the most recent updated list of amphibian and reptile species in the region (35 amphibians and 90 reptiles). Furthermore, based on recent inventories (2007–2013)we establish 40 range extensions of 8 amphibians and 32 reptiles for the southeastern part of the Lacandona rainforest. Four out of these 40 records confirmed the occurrence of Dermophis mexicanus, Eleutherodactylus leprus, Pantherophis flavirufus, and Bothriechis schlegelii in the region.