Medullary thyroid carcinoma (MTC) accounts for 5-10% of thyroid malignancies and occurs either as a sporadic or as a familial form. The familial form is inherited in an autosomal dominant pattern, and it is clinically expressed as multiple endocrine neoplasia (MEN), types IIa and IIb or as familial MTC alone. It is possible to make an early diagnosis in patients who have the familial form of the disease as well as to perform an organ specific localisation regarding possible spread of the disease. Calcitonin is a major product of MTC cells and represent the most used tumour marker for diagnosis and evaluation of prognosis. The purpose of this investigation is to analyse our experience with patients treated for MTC in the period 1980-1993.