We analyzed the medical records of patients admitted to 11 hospitals over a 15-year period, looking for those with metabolically active sporadic pheochromocytomas (Group A) and those in whom the diagnosis was highly suspect but excluded (Group B). Fifty-three patients in Group A and 25 patients in Group B were found. We then devised a scoring system based on the presence or absence of typical symptoms and signs (SSS) and another which also included the results of routine 24-hour urine studies for catecholamines or metabolites (SSLS). The point values given for each symptom and sign were based on those felt to be most characteristic of the disease and points were subtracted if the typical manifestation was absent. Additional points were given if the symptom or sign were paroxysmal. In a high-risk population, the sensitivity of the SSS and the SSLS was 96 percent and the specificity was 64 percent and 88 percent, respectively. The predictive value of a positive SSS was 85 percent and of a positive SSLS was 94 percent. In a large group of patients with essential hypertension (Group C) only 17 of 385 (4.4 percent) had a positive SSS and only one of 385 had a positive SSLS. We feel this scoring system can help detect those hypertensive patients in whom further extensive and potentially invasive evaluation is warranted.