We report here a case of Sipple's syndrome, and we also analyze the relationship between the type of hypertension and urinary excretion of catecholamines in Sipple's syndrome based on the literature in Japan. One hundred and fourteen cases of Sipple's syndrome have been reported in Japan. The hypertension of patients with Sipple's syndrome shows a ratio of fitfull hypertension to continual hypertension of 6 to 1, whereas the ratio is 1 to 1.5 in patients whose pheochromocytoma is not accompanied by Sipple's syndrome. The patients with Sipple's syndrome, being pheochromocytoma can be classified into the adrenaline (U-AD) dominant type and noradrenaline (U-NA) dominant type based on the catecholamine excretion in the urine. The U-AD predominant (U-AD/U-NA greater than 0.4) patients mostly reveal fitfull hypertension, while patients with continual hypertension hardly show U-AD predominant.