The present study was carried out to evaluate the effectiveness and study the impact of anise oil as a natural product against the adults of the cowpea seed beetle, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) under controlled laboratory conditions. The study was made at the biology Department, Faculty of Science, Princes Nora University, Al Riyadh, Saudi Arabia, where the effect of four concentrations of anise oil (5, 2.5, 1.25 and 0.12 mg/l) on the adults of this pest was tested. Results were recorded after three and five days of treatment. The Percentage of mortality of adult insects was estimated. Data statistically analyzed and the toxicity lines were illustrated. Data obtained showed that, all the tested concentrations gave satisfactory results against the cowpea weevil under laboratory conditions and the mortality percentage increased with the increase of the oil concentration and the period after treatment. The percentage of mortality was between 20 and 56.66 % after three days and was between 70 and 83.33 % after five days from treatment at the lower (0.12 mg/l) and higher (5mg/l) concentrations, respectively, and the LC₅₀ value was 4.971 mg/l after three days from treatment.