A new species in the genus Iotonchus Cobb, 1916 from the district South 24-Parganas, West Bengal, India is described and illustrated herein. Fourteen female and seven male specimens of this species were collected. Body large (female: 2.8-3.0 mm; male: 2.3-3.1 mm), J-shaped after fixation, buccal cavity large but narrow (female: 56.6-66.6 × 33.3-36.6 μm; male: 50-56.6 × 26.4-30.0 μm), a small dorsal tooth at the base of the buccal cavity, females amphidelphic, ovary reflexed, sphincter at oviduct-uterus junction, advulval papillae present in female; long tail, caudal pore present, caudal glands conspicuous and spinneret terminal, cuticle at the tail terminus swollen. One female specimen was found possessing two vulva.