Two patients who had removal of seemingly benign pheochromocytomas had recurrences 10 and 14 years later despite normal catecholamine excretion for 7 and 9 years postoperatively. The first patient returned with a myocardial infarction and an apparently solitary recurrence; the second patient with a stroke and metastatic disease. Both patients had recurrence of hypertension and increased catecholamine excretion. They were given phenoxybenzamine and are doing satisfactorily 7 and 9 years after their recurrences. Such patients should be followed after surgery for 15 or more years for early detection of recurrences. Prompt therapy should reduce the risk of undesirable complications.