The essential oils from Mentha longifolia L., and Lavandula dentata L. were evaluated for their insecticidal and repellent activity against adult females of Culex pipiens L. The two oils showed LC₅₀ values of 0.215and 0.217 µl / l, respectively. Lavandula dentata oil showed higher repellent activity than Mentha longifolia oil against adults of Culex pipiens; paraffin oil significantly prolonged the time of protection for the two oils. The longest time of protection was 165 min for L dentata oil, at 1 µl/cm², when the tested oils were applied in paraffin oil. The principle compounds in the two oils were pulegone, l-menthone, 1-8-cineole, eucarvone and borneol for (M. longifolia); and camphor, fenchone, linalool and fenchol for (L. dentata). The two oils were effective as repellent substances when compared with commercial materials. Further studies are needed to isolate the most effective mosquito control agents from these oils.