Heliothis virescens males were more effective in inheriting profenofos resistance than females. The degree of dominance of profenofos resistant alleles was (-0.22) and (+0.27) for the hybrid from crossing susceptible parent with female or male resistant parent, respectively. Resistance to profenofos in H. virescens larvae may be partially incompletely dominant sex linkage gene and incompletely recessive autosomal gene. There is a possibility of a partial cross resistance between organophosphates and pyrethroids through the incompletely recessive autosomal gene, the degree of dominance of cypermethrin resistance gene was (-0.18) or (-0.68), respectively for the hybrid from crossing resistant females or resistant males. Esterase activity measured toward 1-naphthyl acetate in larvae of tobacco budworm may be responsible about big part of profenofos detoxication (r ² = 0.69), however play less role in pyrethroid hydrolysis (r ² = 0.32). There was a specific band with Rm = 0.65±0.05 may be important for hydrolyzing profenofos, this band was more represented in resistance larvae. However no one of susceptible larvae expressed this specific band. Pupae of H. virescens may not be an optimum stage to characterize the biological and biochemical expressions of resistance, esterase activities measured in pupae did not correlate (r ² = 0.077) with those measured in larvae. Topical application technique with H. virescens adults did not express resistance to profenofos or cypermethrin.