During an extensive survey of herpetofauna of the Nicobar Islands, a total of 15 islands were sampled for snakes. A total of 14 species of snakes belonging to 11 genera and five families were recorded. The colubrid Oligodon woodmasoni was recorded for the first time since its description. We also confirm the occurrence of the pitvipers Trimeresurus albolabris and Trimeresurus andersoni . More than 50 new geographical localities have been identified for the species recorded. For the first time ecological and distributional data are provided for the endemic species Trimeresurus labialis , Trimeresurus cantori , Oligodon woodmasoni , Dendrelaphis humayuni , Lycodon tiwarii , and Boiga wallachi . A compilation of the past-confirmed records of snake species and the results of the current study indicate the Nicobar Islands snake fauna is composed of 19 species of non-marine and three species of marine snakes. The highest number of species was observed in forest and the encounter rate was greater in streams, ponds and caves. Grasslands, though extensive in the Central Nicobars, supported very few species. Trimeresurus cantori was identified as the most commonly encountered species in the Central Nicobars. The encounter rate for T. cantori was more than twice the next common species, Trimeresurus labialis .