In the present study, the effects of volatile components of Citrus paradisi, C. aurantium, C. limonium and C. sinensis peel essential oils were investigated on the cowpea adult bruchid, Callosobruchus maculatus (F.). The oils were extracted from the fruit peels using hydrodistillation. The results indicated that the citrus oils had high fumigant activity against adult beetles. The mortality of 1-2 day-old adults increased with concentration and exposure time from 3 to 24 h. The oil of C. paradisi was more effective than those of C. aurantium and C. limonium (The LC₅₀ values were 125, 145 and 235 &Amp;plusmn;1 L^-1 at 24 h exposure, respectively). The oil of C. sinensis proved to be least toxic (LC₅₀ = 269 &Amp;plusmn;1 L^-1). The results suggested that citrus peel oils can be used as potential control measure against cowpea beetles.