Efficacy of several selected insecticides available in the market was tested against the Diamondback moth, Plutella xylostella (L), on cabbage, Brassica oleracea var. capitata (L), in the lowland (University of Agriculture Malaysia farm). In general, the results showed that acephate, methamidophos, and bendiocarb all at 0.1% a.i., Bacillus thuringiensis at lg./l., diflubenzuron at 0.007% a.i., each in 450 I. of water /ha. caused significant reduction (P=0.05) in larval population. These insecticides also provided equal protection against larval damage on young hearting leaves of cabbage. Consistently, the control plots gave significantly lower yield (P=0.05) of marketable heads as compared to the insecticide treated plots.