Eight cases of pheochromocytoma experienced at the department in a recent 8-year period were subjected to a study on their clinical features. Plasma and urinary free catecholamines and urinary vanillylmandelic acid were estimated for biochemical diagnosis. Impaired glucose tolerance was found in 7 cases, and fasting insulin secretion was low only in the patients wih high level of urinary noradrenaline. The main modalities utilized for localization of the tumors were ultrasonography and computed tomography. All patients were treated with an α1-blocking agent for operative preparation. Patients with hypertension and tachycardia were treated with a combination of α1-blocking agent, β-blocking agent and calcium antagonist. The transabdominal approach was performed for surgical incision, and no complications were observed during and immediately after the operation. One patient with histopathologically diagnosed malignant pheochromocytoma, however, is still having high level of urinary catecholamines, of which probable causes are in study.