The present study was conducted at K-block, University of Agricultural Sciences, Bengaluru. Theexperimental material for the present investigation consists of two varieties of Bambara groundnut havinggood agronomic base belonging to different accessions viz., SB-42 (light brown, round shape and whitehilum) and S165A (dark brownish, dark spotted surface and oval shape). Five different concentrations ofEMS 0.1, 0.2, 0.3, 0.4 and 0.5 per cent were used to treat the seeds. After the treatment, the seeds were sownin the field along with control (untreated seeds) to raise M1 generation. The M2 generation was raisedduring 2014 summer season by pooling all the seeds of M1 plants on plant to row basis along with controlplants. In both the varieties of Bambara groundnut, the mutagenic effectiveness and efficiency of mutagenictreatments varied not only between the two varieties but also between the treatments. A concentration of0.3 per cent EMS was more effective than the other concentrations of EMS. Hence 0.3 per cent EMS has beenregarded as LD50 for inducing useful mutations.