Diallel analysis in sesame using ten mutant lines was carried out to study the heterosis and combining ability in inter-mutant hybrids for various quantitative traits viz. plant height, days to 50% flowering, days to maturity, number of capsules per plant, capsule length, number of seeds per capsule, 1000 seed weight, oil content and seed yield per plant. General and Specific combining ability (gca and sca) variances showed major contribution of non-additive gene action for all the characters except for days to maturity. Mutant lines viz. Mutant 274, (10.35) Mutant 699,(5.67) Mutant 353 (5.61) and Mutant 450(3.97) were the best general combiners for seed yield and highest magnitude of standard heterosis was recorded in the cross (Mutant 9 x Mutant 699) 45.2 over CC1 and 108.77 over CC2 (Mutant 181 x Mutant 699) 42.68 over CC1 and 105.26 over CC2 and (Mutant 51 x Mutant 699) 48.78 over CC1 and 114.04 over CC2 these hybrids have been identified as best hybrids from productivity point of view further these high yielding mutants can be tried under different environment to test their stability over locations and to confirm their superiority.