The effect of the type of initial surgery for medullary thyroid carcinoma on the outcome is obscure. Some 40 patients with hereditary medullary thyroid carcinoma underwent either thyroidectomy and modified radical neck dissection (n = 18), subtotal thyroid resection (n = 10), or thyroidectomy (n = 12), partly with selective lymphadenectomy, as initial surgery. Patients who underwent thyroidectomy and modified radical neck dissection as their first operation had higher cure rates and lower morbidity. Thus the initial procedure is decisive for the further outcome in patients with hereditary medullary thyroid carcinoma.