In the present study, we report a case of pheochromocytoma whose high blood pressure was well controlled by single-agent therapy with long-acting nifedipine, in spite of the failure of the combination of labetalol and prazosin in lowering blood pressure satisfactorily. A 48 year old female was first noted to have hypertension (160/100 mmHg) at 45 years of age. Hypertension was not controlled by conventional antihypertensive drugs. She was admitted to Fukui Prefectural Hospital in September, 1985. Her blood pressure on admission was 210/110 mmHg. Extraction of the left adrenal gland containing a pheochromocytoma (30 x 37 x 10 mm) was performed in November, 1985. Her hypertension and abnormally high plasma noradrenaline (NA) concentration (1,760 pg/ml, normal value 40-350 pg/ml) were sustained even after operation. Combination therapy with labetalol (400 mg/day) and prazosin (6 mg/day) was unsatisfactory, and the addition of long-acting nifedipine (40 mg/day) produced a marked decrease in blood pressure. Furthermore, single therapy with long-acting nifedipine was effective. No reduction of urinary NA excretion was observed in our patient during long-acting nifedipine therapy, suggesting that the decrease in blood pressure was not caused by suppression of NA release from pheochromocytoma tissue.