A small catenulid flatworm was isolated from the water samples collected from the River Ganga, West Bengal, India. The identification of the species was performed based on the morphological characters, i.e., body shape and size, ciliated pits, brain lobes, light refracting bodies, excretophores. The specimens fit well with the description of Stenostomum sphagnetorum Papi in Luther, 1960 a species with wide distribution. The genus Stenostomum is the best-known genus of the order Catenulida with reports of over 60 species worldwide; however, this is the first record of the genus Stenostomum from India. A brief description, based on live photomicrographs has been provided.