Laboratory fumigations were conducted at 80 degrees F plus/minus 3 in 20-liter glass bottles containing shelled or in shell peanuts to determine the toxicity of methyl bromide to the larvae and adults of the red flour beetle, Tribolium castaneum (Herbst), and larvae of the Indian-meal moth, Plodia interpunctella (Huebner). Dosages of methyl bromide to produce a 95 % mortality ranged from 6.19 to 13.33 mg/liter for shelled peanuts and from 6.41 to 9.54 mg/liter for in shell peanuts depending on the test insects involved.