Using gamma rays, ethyl methane sulphonate (EMS), sodium azide (SA) and their combinations, various biological parameters were evaluated in M1 generation in three lentil varieties viz., K 75, L 4076 and PL 406. A reduction in germination, root and shoot length of seedling, pollen fertility, survival, plant height and grain yield were noticed. EMS has profound effect on chlorophyll as well as viable mutations in M2 generation. Three types of chlorophyll mutations viz., albina, xantha and viridis were found. Viable mutants were higher in bold seeded varieties than the small seeded variety. Among 14 types of viable mutants recorded, mutants with spreading habit, profuse branching, compactness and tendriller leaves, were induced in higher frequency in PL 406 while mutantsin respect of plant height and leaf size their frequency washigher in K 75.