Many plant essential oils show a broad spectrum of activity against pests or insects. These oils have a long tradition of use in the production of stored products against pests or insects. Recent investigation indicates that some chemical constituents of these oils interfere with the octopaminergic nervous system in insects. Pure essential oils of Cymbopogon citratus and Mentha piperita have been investigated for their efficacy levels against mosquitoes (Anopheles). The two aerated jars labeled a and b, were place 40 mosquitoes each and the Cymbopogon citratus oil and Mentha piperita oil was sprayed inside them respectively. The mortality rate of both green insecticides was then recorded, with respect to time. The above procedure was thus repeated using varying doses of the green insecticide and their mortality rate were also recorded. Result showed that both Mentha piperita and Cymbopogon citratus oils have insecticidal properties, comparatively however, Mentha piperita oil achieved greater mortality (2fold) compared to Cymbopogon citratus oils at the same dose application. It can be concluded that both Cymbopogon citratus oils and Mentha piperita oil are promising natural repellents due to its safety advantage over chemical repellents. Result gene optimum level of 1.0 ml and 1.3ml respectively for (PPO) Mentha piperita oil and (LPO) Lemon Plant oil were recorded, showing that at such concentration, the greatest killer of man can be checked.