The study was conducted to investigate the larvicidal activity of Vernonia adoensis roots methanol - water extract against Culex quinquefasciatus. The plant samples were extracted using methanol and water in the ratio 9:1. From the study the roots of Vernonia adoensis were found to have toxicity against Culex quinguefasciatus with a percentage mortality of 80% at a concentration of 2000 mg/l, 80% at a concentration of 1000 mg/l, 60% concentration of 500 mg/l and 20% concentration of 250 mg/l. The results from this study shows that Vernonia adoensis roots extract can be used as a potential insecticide against Culex quinquefasciatus. More research needs to be done to analyze the specific compounds in the plant which are acting against the larvae.