Eighty-seven snakes representing 6 species in 2 families (Colubridae: Amphiesma vibakari, Elaphe climacophora, Elaphe conspicillata, Elaphe quadrivirgata, and Rhabdophis tigrinus; Viperidae: Gloydius blomhoffii) were collected on Honshu Island, Japan, between 1965 and 1998 and examined for helminths. Gravid individuals of 1 species of Trematoda, Encyclometra japonica, 1 species of Cestoda, Mesocestoides sp. (tetrathyridia), 8 species of Nematoda, Cosmocercoides pulcher, Hexametra quadricornis, Kalicephalus brachycephalus, Kalicephalus costatus, Kalicephalus sinensis, Oswaldocruzia socialis, Paracapillaria kuntzi, and Rhabdias horigutii, and 2 species of Acanthocephala, gravid individuals of Acanthocephalus lucidus and cystacanths of Polymorphidae gen. sp., were found. Fourteen new host records and 1 new locality record are reported.