Abstract: Malaria transmission depends on the competence of selective Anopheles mosquitoes that plays role of intermediate host. The innate immune system of most mosquitoes (non-vectors) is able to completely clear a Plasmodium infection, preventing parasite transmission to humans. Mosquito defense against malaria parasites involves variety of biological processes, among which ROS (Reactive Oxygen Species) are important determinants of parasite invasion to the mosquito. ROS are toxic by-product of cellular metabolism in all living beings. The living cells create potent antioxidant enzymes which detoxify ROS. The detoxifying enzymes are superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), glutathione peroxidase and glutathione reductase. The Glutathione-S-transferases (GSTs) are a diverse family of enzymes involved in a wide range of biological processes. Our previous study demonstrated that elevated GST activity played a role of resistant phenotype (to insecticide) in the mosquito, which is directly related to vectorial capacity and competence. The study of role of GST in mosquito physiology will give an insight in terms of effect of insecticide application on the vector and Plasmodium parasite development inside the vector, which has potential to explore more powerful and effective malaria control tool.