The study was conducted to determine the insecticidal and physiological activity of essential oil from Artemisia annua L. on Indial meal moth Plodia interpunctella (Hübner) in laboratory condition. The yellowish oil of wormwood Artemisia annua L. was diluted in acetone and different concentrations (15%, 11%, 8%, 5.5% and 4%) were assayed on 17 days old larvae. LC 25 , LC 50 and LC 75 were estimated 5.96%, 8.4% and 11.3% respectively after 24 h. The sub lethal doses showed that essential oil reduced adult emergence, longevity of male and female insects, fecundity and fertility of females. Evaluation of toxic vapors on adult insect was also considered and LC 25 , LC 50 and LC 75 were estimated to be 6.35%, 8.13% and 10.45%. There was no difference in mortality on either sex. The protein, carbohydrate and lipid contents of treated larvae were significantly reduced compared with the controls.