A procedure is described for rapidly screening some organophosphorus pesticides in plant extracts without elaborate clean-up. Azinphos-methyl, carbophenothion, diazinon, ethion, malathion, mevinphos and parathion are extracted with acetonitrile and partitioned into hexane before analysis by the thin-layer chromatographic-enzyme inhibition technique. These pesticides, in the presence of apple, beet, carrot, lettuce, pea or potato extractives, are detected on thin-layer chromatographic plates coated with a silica-gel layer. The experiment indicates that the equivalent of only a few milligrams of the original sample is required for semi-quantitative analyses of residues present at, or above, their tolerance levels.