The aim of the present study was to assess the long-term results of adrenalectomy and to evaluate potential risk factors for the persistence or recurrence of hypertension. Forty-five patients with Cushing's syndrome caused by benign cortisol-producing adrenocortical adenomas were evaluated before and for a period of 1 year after surgical cure. When the patients were classified into two groups according to whether their preoperative BP was more (HBP group) or less (NBP group) than 140/90 mmHg, the BP level was found to be continuously higher in the HBP group than in the NBP group during the year after surgery. This finding suggests that the preoperative BP level in Cushing's syndrome may be a determinant factor for persistent hypertension after surgery (P<0.05). In addition, a correlation was found between postoperative BP level and duration of hypertension (P<0.05), but no relationships were found between postoperative BP levels and other factors, including age, BMI, tumor size, serum cortisol, aldosterone, potassium, total cholesterol, or glucose levels. The above findings indicate that intensive control of preoperative BP to maintain it below 140/90 mmHg with antihypertensive medication is a very important means of improving prognosis for postoperative BP. Immediate diagnosis and surgical treatment to reduce the duration of hypertension are also crucial for the long-term BP prognosis.