We report the molecular-phylogenetic identification of larvae of the nematode genus Gnathostoma Owen, 1836 collected from a snake, Ptyas koros Schlegel, in Laos and adult worms from the stomach of a dog in Thailand. DNA was extracted and amplified targeting the partial cox1 gene and the ITS-2 region of ribosomal DNA. Phylogenetic analyses indicated that all five advanced third-stage larvae and seven adult worms were Gnathostoma spinigerum Owen, 1836. This is also the first molecular evidence of infection with G. spinigerum in a snake from Laos., Jurairat Jongthawin, Pewpan M. Intapan, Oranuch Sanpool, Penchom Janwan, Lakkhana Sadaow, Tongjit Thanchomnang, Sakhone Laymanivong, Wanchai Maleewong., and Obsahuje bibliografii