Azadirachtin is one of the successful botanical pesticides in agricultural use with a broad-spectrum insecticide activity, but its possible transgenerational effects have not been the object of much attention. The effects of sublethal doses of azadirachtin on life-table traits and oviposition behaviour of a model organism in toxicological studies, D. melanogaster, were evaluated. The fecundity and oviposition preference of flies surviving to single azadirachtin-treated larvae of parental generation was adversely affected resulting in a reduction of number of eggs laid and increasing aversion to this compound over two successive generations. In parental generation, early exposure to azadirachtin affects adult's development by reducing the number of organisms, delayed larval and pupal development; male biased sex ratio and induced morphological alterations. Moreover, adult's survival of the two generations was significantly decreased as compared to the control. Therefore, Single preimaginal azadirachtin treatment can affect flies population dynamics via transgenerational reductions in survival and reproduction capacity as well as reinforcement of oviposition avoidance which can contribute as repellent strategies in integrated pest management programs. The transgenerational effects observed suggest a possible reduce both in application frequency and total amount of pesticide used, which would aid in reducing both control costs and possible ecotoxicological risks.