The Housefly, Musca Domestica L. (Diptera: Muscidae), Is One of the Most Common Insects, Intimately Associated With Human Settlements, Food, and Utensils. Botanicals Are the Most Promising Source and Under Extensive Trials For Their Biological Activity Against Various Pests. the Strong Inhibition of Acetylcholinesterase (Ache: Ec 184.108.40.206) Is the Principal Underlying Mechanism of Action of Most of the Potential Insecticides. Keeping These Facts In View, the Present Study Investigated the Effects of Ethanol Extracts of Leaves of Annona Squamosa (Annonaceae) and Calotropis Procera (Asclepiadaceae) on the Activity of Ache In Different Developmental Stages of M. Domestica. the Activity of Ache Was Determined According to the Method of Ellman Et Al. 1961. the Exposure of These Extracts Caused Significant Inhibition of the Ache Activity. the High Concentration (10%) of Extract from the Leaves of C. Procera Exhibited Maximum Inhibitory Effects (56%) on the Ache Activity from All the Three Developmental Stages of the Insect Tested. the Results Suggest That These Plants May Prove to Be the Probable Candidates For the Development of Bioinsecticides to Control the Population of M. Domestica As the Safer, Ecofriendly and Economic Alternatives to the Synthetic Insecticides.