Analytical methodology for the separation and characterization of s-triazine herbicide residues in urine was developed. In the sample preparation procedure developed, a urine sample at pH 12 was extracted with hexane three times, using sodium chloride as an emulsion inhibitor. The combined hexane extract was dried by passing it through a sodium sulfate column and concentrated by rotary evaporation. The sample was transferred to a graduated centrifuge tube and further concentrated to 0.5 mL under a stream of dry nitrogen. The sample was analyzed by gas chromatography using the Hall electrolytic conductivity detector (HECD) in the nitrogen-specific mode. The method is advantageous in that it is simple and fast, lending itself to use as a routine method by technical personnel. © 1979, American Chemical Society. All rights reserved.