Among 319 patients with Graves-Basedow disease who were operated upon in surgical department of The Institute of Endocrinology in Belgrade between 1978 and 1990, thyroid carcinoma was found in 15 cases (4.7%). In 10 patients carcinoma was suspected before operation because of the node in diffuse goiter, while in 5 patients carcinoma was found unexpectedly. Tumor was smaller than 1 sm in only one patient. Nine patients had papillary carcinoma, 4 had follicular and 2 had medullary carcinoma. One patient with medullary carcinoma had been treated previously with radioactive iodine. In 2 patients carcinoma was found in recurrent goiter after primary operation, patients with thyroid carcinoma in Graves-Basedow disease were averaging about 10 years older than other patients with Graves-Basedow disease treated surgically.