Anaplastic giant cell carcinoma of the thyroid is a rare but highly malignant tumor. At the Karolinska Hospital in Stockholm, surgery, chemotherapy, and radiotherapy have been used separately or in various combinations in 81 patients admitted with this diagnosis during 1971-1997. In this study, we present the various multimodality treatment regimens and their changes over the years and the subsequent differences in survival and local tumor control. Overall, eight patients (10%) survived more than 2 years. All survivors were treated with combinations of chemotherapy, radiotherapy, and surgery. Among the patients who died, local tumor control was achieved by the therapy given in many cases. The results suggest that our current strategy with a combination of preoperative hyperfractionated accelerated radiotherapy, doxorubicin pre- and postoperatively, and debulking surgery whenever possible results in better local tumor control and an increased chance of survival.