In the present study, the crude ethanol extracts of Calotropis procera and Annona squamosa leaves have been screened for their larvicidal activities against Musca domestica. The third instar larvae of housefly were treated with the different concentrations of both the extracts by dipping method for 48 h. The LC 50 values of the extracts of C. procera and A. squamosa leaves were found to be 282.5 and 550 mgl -1 , respectively. The phytochemical analysis of these extracts suggested presence of alkaloids as the major component. The larvae were exposed to 5 and 10% concentrations of the LC 50 value of each extract along with their control sets to evaluate their effect on metamorphosis, nucleic acid and protein content in different developmental stages. The leaf extract of C. procera was found to be more active in terms of insecticidal potential. The data indicate that the leaf extracts of these plants may be utilized as the probable candidates for the development of bioinsecticides to control the population of Musca domestica as safer and economic alternatives to the synthetic insecticides.