In 1983 a large family with MEN-1 (designated Tasman 1) was identified in Tasmania. Kindred screening and case follow-up over the subsequent 15 years has yielded data on over 160 MEN-1-affected patients. Hyperparathyroidism is present in over 60% of gene carriers by age 20 years and 95% by age 30 years. Hyperplasia is the characteristic pathological finding. Kaplan-Meier analysis indicates hyperparathyroidism recurs in the majority of patients despite near-total parathyroidectomy. Gastrinoma, 'nonfunctioning' pancreatic adenoma and insulinoma occur in up to 60, 50 and 10% of patients, respectively. Metastatic gastroenteropancreatic (GEP) tumours develop in up to 35% of family members, being frequent in some branches of Tasman 1, whilst rare in others. Pituitary disease developed in 19% of patients. Prolactinoma and 'nonfunctioning' adenoma account for 76 and 24%, respectively, of pituitary abnormalities. Prolactinomas exhibit clustering within branches of the Tasman 1 kindred. Adrenal adenomas occur in 36% of patients. The majority of adrenal lesions are benign and nonsecretory and develop in association with pancreatic neoplasia. Carcinoid tumours are uncommon but important malignancies. Malignant thymic carcinoid occurs in male patients, whereas bronchial carcinoid occurs predominantly in women. Prior to recognition of MEN-1 in Tasman 1, complications of hyperparathyroidism and malignancy accounted for the majority of patient mortality. Since commencement of prospective screening, malignant GEP tumours and cardiovascular disease have become the most prevalent causes of death amongst MEN-1-affected patients.