A study was conducted with soybean (1) to assess the effects of a physical mutagen gamma rays, and a chemical mutagen EMS, on two released soybean varieties viz., CO1 (indeterminate) and CO2 (determinate) and (2) to analylse the induced variations in these varieties. For inducing macro and micro mutations, the doses applied were 20, 30, 40, 50 and 60 kR of gamma rays and 5, 10, 15, 20 and 25 mM of EMS. In initial evaluation trials, the germination percentage and survival of seedlings showed a dose dependant reduction for both the mutagen (gamma rays and EMS) in CO1 and CO2. The prohit analysis on percentage of mortality revealed the relative sensitivity of two varieties. It was observed that CO1 tolerated the highest dose of gamma rays and EMS.