Momordica janarthanamii, a new species is described and illustrated from Nashik district of Maharashtra state, India. The new species is closely related to Momordica dioica Roxb. ex Willd. Colored photographs, distribution, ecological note and economical value of the new species are provided. A key for the dioecious species of Momordica from India has also been provided to facilitate identification.

The specimens of new species of Momordica were collected from Karanjali ghat (Kumbharbari), Nashik in July 2020. The morphological characters were studied under Leica EZ4 Stereo Zoom microscope. Diagnostic characters of the unknown species were compared with protologue and type specimens of its closely related species i.e. M. dioica. Photographs in the field and different parts of the plants were taken by using M50 Canon camera. The type specimens have been deposited at BSI, CAL and SUK herbaria.