In a study involving two sites in western Canada, residues of the herbicide metribuzin in lentil were monitored by gas chromatography following postemergence application at 0.28 kg a.i. ha−1. On the day of spraying, initial residues in lentil green foliage were of the order of 1 mg kg−1. Metribuzin residues in the green foliage continually decreased with time to non-detectable levels (< 0.02 mg kg−1) at 42 d after application. No metribuzin residues were detected in the straw or mature seed. Key words: Metribuzin, 4-amino-6-(1,1-dimethylethyl)-3-(methylthio-1,2,4-triazin-5(4H)-one; lentil, Lens culinaris Medic., residues, residue analysis, gas chromatography