The peel powder of Punica granatum, extracted with petroleum ether, was proved to have potential toxicological effects against third instar larvae of Culex pipiens. The median lethal dose (LC50) value was found to be 95.6632 ppm. Qualitative phytochemical screening of pomegranate peel extract was assessed by standard methods. The phytochemical constituents present in petroleum ether extract of Punica granatum peel were phenols and Saponins. The mid gut of the treated larvae was investigated histopathologically and ultra-structurally. The tested extract induced a severe damage to the larval midgut epithelial cells; showing swollen, lysed and displayed clear destruction in the peritrophic membrane and brush border. Also, several changes in cell organelles including destruction of the cell membrane, microvilli, mitochondria, nuclei and cytolysis of gut epithelial cells was observed.