Laboratory studies were conducted to investigate the toxic, growth-inhibiting and antifeedant/deterrent effects of neem derivatives on spotted bollworm and its effects on the parasitism potential and adult emergence of Trichogramma chilonis. Neem oil at 1, 1.5 and 2 % and neem seed water extract at 3 % concentrations not only significantly killed more spotted bollworm larvae but also reduced the number of surviving larvae that pupated. However, neem oil and neem seed water extract at 1 % did not affect adult emergence in the tested insect. Neem oil at 1.5 and 2 % and neem seed water extract at 3 % significantly reduced the number of larvae on treated leaves. Percentage parasitism of bollworm eggs by T. chilonis was significantly reduced when they were placed on leaves treated with 2 % neem oil, Polytrin-C® (40 % profenofos 4 % Cypermethrin) and 3 % neem seed water extract, but adult emergence of T. chilonis was not affected by any of the neem treatments. Similarly, the F₁ progeny parasitized the bollworm untreated eggs normally and the emergence of F₂ progeny was not affected by neem treatments. However, Polytrin-C® significantly reduced parasitism of the bollworm eggs by T. chilonis and adult emergence of the parasitoid.