During a period of ten years, 1977-1986, 778 patients were treated for diseases of the thyroid gland. Of these, 678 were benign and 100 malignant. The reasons for referral were most frequently a lump in the thyroid gland, possibly with suspected malignant changes. In the group with benign conditions, there were five times as many women as men whereas the proportion in the malignant group was 1.5 to 1. Technetium-scintigraphy and fine-needle aspiration were undertaken routinely preoperatively. As a rule, none of the preoperative investigations could reveal with certainty whether the condition was benign or malignant but, in certain cases, the investigations may provide indication and guidance for the continued treatment or control of the patients concerned. Treatment with particular attention to the recurrent nerve and the complications, particularly recurrent paresis, is mentioned.