Abstract : The present investigation was undertaken to assess the larvicidal potential of the leaf extract from the medicinal plant Croton sparciflorus Morong (C. sparciflorus) against the medically important mosquito vectors, Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Twenty five III instar larvae of three mosquitoes are exposed to different concentration (50-250) and were assayed in the laboratory by using the protocol of WHO 2005; The 24 h LC50 values of the C. The Sparciflorus leaf extract was determined following Probit analysis. Among the plant extract tested against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus the pronounced lethal activity was recorded against C. sparciflorus extract in the experimental larvae of A. Stephens with an LC and LC 50 90 value of 28.88 and 65.35 ppm. It is accomplished that the highest larvicidal activity against A. stephensi was obtained with ethyl acetate extract of C. sparciflorus. The present investigation revealed that the possible utilization of C. sparciflorus to control the mosquito menace to a greater extent. Thus, paving the way for further exploration of identification and isolation of active principles present on the selected plant.