Sensitivity tests were performed according to the World Health Organization protocol (WHO) for three essential oils (Citrus aurantium (bitter orange) Citrus sinensis (orange) and Pistacia lentiscus) and four chemical insecticides (Malathion Temephos Fenthion and Fenitrothion) used as a positive controls. Essential oils have shown an interesting larvicidal activity against Culex pipiens, with an interesting lethal doses (LD50= 35 ppm and LD90=70 ppm) in the case of Citrus aurantium essential oils and (LD50= 64 ppm and LD90 = 120 ppm) using Citrus sinensis while the LD50 and LD90 were, respectively, in the case of Pistacia lentiscus 62ppm and 160ppm. Chemical insecticides, used as a positive control, showed a significant larvicidal activity. The larvicidal activity of essential oils could have a great interest in the domain of vector control. This is because of problems caused by the use of chemical insecticides (environmental pollution, resistance, hazards to human health).