Four new species of the genusIotonchus, viz.,I. nayari, I. kherai, I. khani andI. heynsi are described.I. nayari comes close toI. risoceiae but differs in having shorter body and longer spicules compared to body length.I. kherai differs fromI. indicus in body size, shape and size of buccal cavity and presence of males and fromI. risoceiae in the shape of buccal cavity and subventral opening of caudal glands.I. khani differs fromI. chantaburensis in having shorter tail, poorly developed caudal glands and spinneret and absence of distinct valve between oviduct and uterus.I. heynsi differs fromI. longicaudatus by having an indistinct terminal caudal gland opening, non-cuticularised vagina and absence of sphincter at oviduct-uterus junction and fromI. trichurus by the size and anterior position of dorsal tooth. A key to Indian species of the genusIotonchus is provided.