The house fly Musca vicina Macq is  found in human habitat. Insecticides usually destroy the natural enemies of a given pest more than the pest itself. The penetration of substances, through the integument of a living insect, is restricted by the structure of the cuticle. Numerous studies have been carried out on the insecticidal properties of different plant extracts. Family Meliaceae represents one of the most important plants in this respect, as it contains the neem tree Azadirachta indica A. Juss and the chinaberry tree Melia azedarach (the Egyptian common name is Zanzalacht). The discovery of insecticidal properties of Melia azedarach  created quite a stir among entomologists interested in the practical uses of insect. The Musca domestica vicina, dissected and examined in this study, were all produced from a colony raised at the laboratory of the Department Zoology, Faculty of Science, University of Alexandria. Fresh leaves and ripe fruits were collected from the chinaberry trees, Melia azedarach, found in the garden of Faculty of Science at Shatby, Alexandria University. Leaves and fruits were washed in running tap water and air dried for several days, then were put in an oven at 60°C until reaching a constant weight, afterwards, they were pulverized by using a hummer mill. Extraction was conducted in a 250 ml Soxhlet apparatus using methanol as a solvent. However, no separation of fat materials was done. The extraction period lasted a total of 20 hours over four days until the chinaberry leaves and fruits became colorless. The fly fertility was determined as the number of eggs hatched in relation to the total number of eggs laid. Results showed that adults fertility was affected by treatment with Melia azedarach extract.