Labile high blood pressure and associated complaints (eg, severe headache, palpitation, and vague discomfort in the chest) in a 28-year-old woman with pheochromocytoma were stabilized by adding nifedipine to the conventional regimen of alpha- and beta-blocking agents. Electrocardiographic (ECG) data (ST depressions, prolonged QT intervals, and giant negative T waves during a hypertensive attack) and findings in biopsied myocardial specimens (slight cell infiltration composed mainly of lymphocytes associated with interstitial fibrosis) had suggested the presence of catecholamine cardiomyopathy. Oral administration of 10 mg of nifedipine alone had rapidly resulted in normalization of blood pressure and complete relief from associated signs and symptoms. Because conventional preoperative treatment with alpha- and beta-blockers did not alleviate the hypertensive attacks, a 20-mg long-acting nifedipine tablet was added to the regimen. The effect of twice-daily administration of a 20-mg long-acting nifedipine tablet (combined with alpha- and beta-blockers) was so prominent that it was possible for the patient to undergo surgery for removal of the right adrenal gland and a 4-cm tumor at the gland. After surgery there were no abnormal ECG findings.