A 63-year-old female presented with the extremely rare occurrence of an aldosterone-secreting adrenocortical adenoma as part of the syndrome of multiple endocrine neoplasia type 1 (MEN1). Only two other MEN1 patients were reported in the literature with hyperaldosteronism. The patient's MEN1 syndrome consisted of the association of primary hyperparathyroidism due to parathyroid adenoma, a prolactinoma, and a toxic multinodular goiter. Elevated basal and meal-stimulated serum PP levels without demonstrable pancreatic tumor were also found. Genetic analysis of the aldosterone-secreting adenoma with DNA markers localized on chromosome 11 showed loss of heterozygosity in tumor DNA. Since the MEN1 syndrome is caused by loss of the tumor suppressor gene on chromosome 11 in the 11q13 region, it is probable that the same mechanism is associated with the formation of the adrenocortical adenoma.