Insecticidal property of essential oils obtained from 22 selected medicinal plants against adult of saw-toothed grain beetle, Oryzaephilus surinamensis (Linn.) was investigated by using fumigation method.As preliminary test, each plant essential oil was applied in vial sized 40 cm3 with concentration of 25 μl/L air essential oils and 95% ethanol was used as the control.The mortalities of saw-toothed grain beetle were observed at 24 h.The result showed that plant essential oils namely;clove (Syzygium aromaticum (Linn.) Merr.&L.M.Perry, cinnamon (Cinnamomum bejolghota (Buch.-Ham.) Sweet),galanga (Alpinia galangal Linn.),cassumunar ginger (Zingiber cassumunar Roxb),lemon grass (Cymbopogon citratus (Dc.ex.Nees)),citronella grass (Cymbopogon nardus Rendle),sweet basil (Ocimum basilicum Linn.),star anise (Illicium verum Hook.f.),marigold (Tagetes erecta Linn.) and dill (Anethum graveolens Linn.) could kill more than 75% adult beetle at 24 h.Fumigant effect of those essential oils at various concentrations of 0, 5, 10, 15, 20 and 25 μl/L air against the beetle was then evaluated.Based up on 24 h LC50 values, the essential oils of star anise showed the most toxic effect to the insect in which presented high activity of 7.170 μl/L air, followed by the essential oils of dill, marigold, lemon grass, clove and sweet basil, showed of 11.381, 12.528, 12.893, 15.139 and 19.429 μl/L air, respectively.