60 patients suffering from primary hyperparathyroidism were operated during the period from 1980 till september 1988. The operation was successful in 55 cases. Most patients had single adenomas of the parathyroid glands. There was only one case with a four-gland-hyperplasia and one case with a parathyroid carcinoma. Rare observations were: one woman with a truly recurrent primary hyperparathyroidism, two patients with a papillary carcinoma of the thyroid gland in addition to the hyperparathyroidism and one patient with a large cystic parathyroid adenoma. Most of the patients had severe clinical symptoms of the primary hyperparathyroidism, mainly renal stones, in some cases bone changes. Only three patients were asymptomatic.