The aim of this study was to investigate the role of multimodality treatment in patients with anaplastic thyroid carcinoma. From 1992 to 1999, 39 consecutive patients with a histologically or cytologically proven anaplastic thyroid carcinoma were referred to the Thyroid Center of Padua General Hospital. There were 28 females and 11 males with a median age of 69 years (range 39-88 years). About one-third of patients had a history of preceeding nodular goiter. Two patients had areas of differentiated thyroid carcinoma at histological examination. Local disease was present in 26 patients while distant metastases, mainly to the lung, were present in 22 at diagnosis or quickly developed during the observation period in all the others except one. Thirty-two patients were previously untreated: 9 of them were in good general condition, 1 had limited lung metastases, and the tumor mass was considered resectable by the surgeon. These 9 patients were treated with cisplatin once a week and radiotherapy (RT) 36Gy in 18 fractions over three weeks, followed by total thyroidectomy (TT) and by further chemotherapy (CHT) with adriamycin and bleomycin in 4 patients. Seven patients, 3 with lung metastases at diagnosis, had undergone TT, followed by RT in 5, in another hospital and were subsequently referred to our center due to the presence of distant metastases. Therefore, a total of 16 patients (Group 1) was treated with TT, RT and CHT in various order. Nine patients with distant metastases at diagnosis (Group 2) received CHT; one of them had a disappearance of lung metastases and was then treated by TT and further CHT. Group 3 consisted of 14 elderly patients in poor general conditions; 4 of these received local RT, while the remaining did not receive any treatment. Four complete responses were seen in patients from Group 1, and 1 from Group 2. One patient without distant metastases at diagnosis is alive and free of disease 6 months after TT and adjuvant CHT, and 12 months after diagnosis. Three had long-term survival (14, 24, 27 months) with a disease-free interval of 6-8-10 months. The patient from Group 2 who was treated in a second time by TT is alive without disease after 60 months. Median survival rate was 11 months for Group 1, 5.7 months for Group 2 and 4 months for Group 3. In some patients multimodality treatment (TT, RT and CHT) is associated with increased survival. Nine out of 16 patients, who underwent surgery and complementary treatment, had no local progression. In all but one distant metastases developed, mainly in the lung, during or after post-surgical CHT. The best results were obtained in younger patients with less advanced disease. Early diagnosis is mandatory. Only a few patients responded to CHT, confirming that anaplastic thyroid carcinoma is often resistant to anticancer drugs. Our experience with combination modalities suggests that aggressive and appropriate combinations of RT, TT and CHT may provide some benefit in patients with anaplastic thyroid carcinoma. Preoperative CHT and RT may enhance surgical resectability of the primary tumor.