Vegetable oils at the rate of 1 ml/kg of bean seed, Phaseolus vulgaris L., provided a high level of control against attack of a bruchid Zabrotes subfasciatus (Boheman). At 5 or 10 ml/kg bean seed, complete control was achieved and lasted over 75 days for some oils. Crude oils provided significantly better protection than purified oils, and the level of control of the different oils varied significantly. The oils increased adult mortality and reduced oviposition, egg hatching, and number of adult progeny. Oil treatment of larval-infested beans at 5 ml/kg significantly reduced progeny adult emergence. Manual application of oils provided significantly less control than tumbler application at 1 ml/kg. Both oil treated and nontreated beans germinated equally well. Water absorption of oil-treated and untreated beans soaked for 24 h was the same, independent of length of storage after oil application. Oil applications are cheap (0.5% of market price of beans in Colombia), safe, and easy to do.