ABSTRACT The Soil Conservation Service Curve Number (SCS-CN) method is one of the popular method to determine the depth of surface run-off. The method takes into account the important parameters in the catchment such as soil moisture content, land use land cover etc. The present study focuses on determining the SCS-CN for the lower Mahi river basin located in the western part of India. The necessary data was collected from India-WRIS website. The entire lower Mahi basin is divided into small watersheds with a unique identity. Weighted curve numbers for all the watersheds are calculated and SCS-CN for entire Lower Mahi Basin is then determined.