The direct toxicity of the essential oil, Ocimum basilicum L. to females of six species of predacious mites of the family phytoseiidae was tested. The phytoseiid mites tested namely, Typhlodromus athiasae Porath and Swirski, Euseius yousefi Zaher and El-Borolossy, Amblyseius zaheri Yousef and El-Borolossy, Amblyseius deleoni (Muma and Denmark), Amblyseius swirskii Athias-Henriot and Amblyseius barkeri (Hughes). Sweet basil oil was highly toxic to females E. yousefi and was relatively intoxic to females A. swirskii. The essential oil has a close toxic effect for predator species, T. athiasae and A. barkeri. With the exception of A. zaheri, females of all predacious mites tested suffered a depression in reproduction and food consumption when treated with sweet basil oil at conc. 2%.