Essential oil was obtained by hydro-distillation and the chemical composition of the leaf essential oil was analyzed using gas chromatography-mass spectrometry. The mosquitoes were reared in the vector control laboratory and twenty late III instar larvae of three mosquito species were exposed to based on the wide range and narrow range tests, essential oil was tested at 50, 100, 150, 200 and 250 ppm and each compound was tested at various concentration (5-75 ppm) and were assayed in the laboratory by using the protocol of WHO 2005; the 24 h LC50 values of the C. anisata leaf essential oil and their major compounds were determined following Probit analysis.