Investigations of herpetological biodiversity were conducted at two adjacent localities of southern Laos. Our surveys focused on the Boloven Highlands and the adjacent lowland area of the Xepian National Biodiversity and Conservation Area. A preliminary list of 75 species (22 amphibians, 1 chelonian, 25 lizards, and 27 snakes) is established, of which two are undescribed, and 17 are new records for Lao PDR (five amphibians, 12 reptiles), including a smake species collected in Vientiane. Two species recorded from southern Laos belong to the Indo-Malayan fauna (Kaloula baleata and Gonocephalus grandis). A brief comparison is made with other areas of Southeast Asia.