We developed a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method to measure metabolites of atrazine, phenylurea, and sulfonylurea herbicides in human urine. The metabolites measured in the method include atrazine mercapturate, desethyl atrazine, and desisopropyl atrazine as markers of atrazine exposure; dichlorophenyl urea, dichlorophenylmethyl urea, diuron, and linuron as markers of phenylurea herbicide exposure; and dimethoxypyrimidine, dimethylpyrimidine, and methoxymethyl triazine as markers for sulfonylurea herbicide exposure. The metabolites were extracted from urine by simple solid-phase extraction using a mixed-bed cartridge and were analyzed by HPLC-MS-MS. Quantification of the atrazine metabolites was achieved using isotope-dilution calibration. The remaining metabolites were quantified using similarly structured chemicals as internal standards. Extraction recoveries ranged from 88% to 104% (n = 5). Limits of detection for the entire method ranged from 0.125 to 1 ng/mL, and the average relative standard deviation of repeat measurements was about 13% (n = 30).