The evaluation of the role of the assassin bug, Coranus africana El-Sebaey was studied for suppression of different populations of the cotton aphid, Aphis gossypriGlover in cucumber and squash fields at Fayoum governorate during the successive years, 2005 and 2006. C ahicana was released in the ratio of one predator / plant against three levels of A. gossypilinfestation in cucumber and squash fields. Reduction percentage of A. gossym7 infestation differed according to the release of predator in each treatment. In case of high infestation, the reduction was (99.9 & 92.86 %) during the first and the second years,of the investigation, respectively in cucumber field opposed to (88.6 % and 90.1 %) in squash field throughout the two successive years of the study. Complete eradication of the pest population was achieved when, the infestation level was low or moderate in two crops. The basic yield parameters expressed as the weight of fruit and number of fruits / plant during the two years of the investigation in the two crops.