Azadirachtin is the most active substance separated from Azadirachta indica. It acts destructively on numerous species of insects and mites. The aim of the presented investigations was to determine the effect of azadirachtin on one of the most dangerous pests of cabbage plants, Pieris brassicae, and on its natural enemy, Apanteles glomerarus. The results of the field observations did not show any repellent effect of azadirachtin relating to laying their eggs cabbage butterflies. However, a significant effect of the azadiraehtin solution on reduction the number of cabbage butterfly caterpillars (it was more distinctly marked in respect to young larva stages) as well as on limited feeding by caterpillars. No negative influence of azadirachtin on a parasite of Pieris brassicae caterpillars, Apanteles glomeratus was distinctly shown.