The clinically important malignancies are characterized on the basis of 257 primary surgical procedures performed between 1973 and 1990 (9.1 % of all thyroid operations during this period). Our own proceeding is characterized both in diagnostics and surgical technique in primary and recidive operations under special regard of a modified lymph node dissection. Obligatory and facultative adjuvant therapies are described. The follow-up schedule, which has found to be essential for the individual prognosis, should be discussed.