essential oils of eight plants growing in egypt were isolated by hydrodistillation. the chemical composition of the isolated oils was examined by gas chromatography/mass spectrometry (gc-ms). in the contact toxicity assay, the oils of mentha microphylla and artemisia judaica were the most potent against sitophilus oryzae. when tested against tribolium castaneum, the oils of m. microphylla, eucalyptus camaldulensis and a. judaica showed the highest activity among the test oils with m. microphylla being the most potent. in the fumigant assay, the oil of m. microphylla displayed the strongest insecticidal activity against s. oryzae (lc50=0.21 l/l), while the oils of lantana camara (lc50=29.47 l/l) and e. camaldulensis (lc50=30.81 l/l) revealed good activity. in the case of t. castaneum, the oil of m. microphylla (lc50=4.51 l/l) was the most effective, followed by citrus reticulata (lc50=19.47 l/l) and schinus terebenthifolius (lc50=20.50 l/l). the most interesting finding in this study is the potent contact and fumigant toxicity of m. microphylla oil against s. oryzae and t. castaneum. these results suggested that m. microphylla oil could be used as a potential control agent for s. oryzae and t. castaneum.