Patients with primary aldosteronism show relatively high rates of hypertension after adrenalectomy, but the risk factors for postoperative hypertension remain unclear. Forty-six patients with primary aldosteronism (PA) who had undergone adrenalectomy between 1976 and 1998 were enrolled in this study. Follow-up information including blood pressure (BP) and cardiovascular complications was collected by means of correspondence or telephone contact. At discharge BP was normalized in 34 patients (72%); hypertension persisted in the remaining 12 patients, but BP control was significantly improved. The patients who remained hypertensive at discharge had longer durations of hypertension than did those with normalized BP. After an average follow-up period of 12.2 years, 16 of 34 BP-normalized patients (47%) had recurrent hypertension. Age at adrenalectomy, preoperative serum creatinine level and systolic blood pressure at discharge were significantly higher in patients with recurrent hypertension than in those without it. A multivariate logistic regression analysis revealed that only the level of serum creatinine was independently associated with the incidence of recurrent hypertension. Patients with serum creatinine of 0.9 mg⁄dl or greater had significantly higher rates of recurrent hypertension than those with lower values of serum creatinine. Cardiovascular complications occurred in 5 patients prior to the surgery and in 2 patients during the follow-up period. Although the severity of renal involvement is subclinical, renal damage may play an important role in the development of hypertension during a long period after adrenalectomy in patients with PA. (Hypertens Res 2002; 25: 11-18)