Abstract: Application of plant essential oils has been considered as an important feedingdeterrence in integrated pest management (IPM) programs. In this study, we evaluated the effectsof Salvia mirzayanii (Rech. F. and Esfand) oil on the nutritional indices of adults of Triboliumconfusum (J. du Val.) at 27± 1ºC, 50± 5% RH in continuous darkness. Nutritional indices ofadults were investigated at different concentrations from 925.92 to 4629.62μl/l air. In a no-choiceexperiment, a flour disc bioassay was used to test nutritional indices such as relative consumptionrate (RCR), relative growth rate (RGR), efficiency of conversion of ingested food (ECI) andfeeding deterrence index (FDI). All of the indices varied significantly as concentration of theessential oil increased. Increasing oil concentration from 925.92 to 4629.62μl/l air reduced RCRfrom 0.19 to 0.07mg/mg/insect as well as RGR from 0.14 to 0.02mg/mg/insect, respectively. ECIwas reduced from 77.21 to 39.47% at the same concentrations. However, FDI of T. confusumadults was increased significantly from 6.04 to 64.27% with increasing concentration from925.92 to 4629.62μl/l air, respectively. Findings indicated that S. mirzayanii oil could toxicallyinterfere severe dietary effects in adults of T. confusum. Therefore, S. mirzayanii oil could be aproper antifeedant agent for T. confusum.