The authors operated in 1994-2000 at the Surgical Clinic, Faculty Hospital Plzen a total of 793 patients on account of thyroid disease. This group comprised 57 patients with malignant thyroid disease. The mean age of the operated patients was 48.8 years (range 12-89 years). Three patients (0.38%) died within 30 days after operation. The postoperative morbidity was 6.1%. A lesion of the recurrent nerve was recorded during the postoperative period in 24 patients (3.03%) and had a declining trend. Postoperative hypoparathyroidism was recorded in 5.8% (n = 46) injuries of the neighbouring organs in 1.02% (n = 8), oedema of the larynx in 18 patients, i.e. 2.3%. On the whole the authors observed a decline of postoperative complications during the investigation period, the number being lowest in 2000 associated with the number of performed thyroid operations and a change of the surgical strategy.