Residues of the herbicide dinoseb were determined gas chromatographically in lentils which had been treated at two locations in Saskatchewan with post‐emergence applications of dinoseb at 1.4 and 1.7 kg ha−1. Herbicide residues, determined at selected times after application, were not detected at the limit of detection of the analytical method (0.05 mg kg−1) in either the seed and straw at maturity, or in the green foliage six to eight weeks after application. Recoveries of dinoseb were 76% from fortified green foliage at the 0.1 mg kg−1 level, and 64% from fortified seed at the 0.05 mg kg−1 level.