A new chromatoelectrophoretic urine test based on the quantitative assay of normetanephrine (NM), metanephrine (M), and 3-methoxy-4-hydroxyphenylglycol (G) in a casual urine specimen was used to detect pheochromocytomas. Urine specimens from 40 patients with pheochromocytoma, 50 normotensive subjects, and 25 primary benign hypertensive subjects were analyzed for NM, M, and G using the chromoelectrophoretic test, and the results compared with other tests for pheochromocytoma based on the urinary assay for 3-methoxy-4-hydroxymandelic acid (VMA). Correct results were obtained in all specimens with the chromatoelectrophoretic test as opposed to several equivocal results with the tests that analyze for VMA.