Some of commercial pesticides used in Egypt were examined in laboratory against first generation of Daphnia longispina. The tested animals were collected from Kafr El-zayat district, Egypt and acclimatized in laboratory until used. The examined compounds were imidaclopride, indoxcarb and pyriproxyfen. It is evident from LC50 (96 hrs) values of the compounds that, indoxcarb is highly toxic, while pyriproxyfen is the lowest one. On the other hand, imidacloprid induced LC50 (3.4 ppm; 24 hrs) and decreased to 104 ppm after 96 hrs. The obtained data declared that, Daphnia is a very useful tool for screening pesticides pollution and evaluate their acute toxicity
