Summary Skeletal metastases from thyroid cancer are poorly responsive to medical or radioiodine treatment. Bone destruction in skeletal metastases results from osteoclast-induced bone resorption. Therefore, a new approach in the therapy of bone metastases consists in using aminobisphosphonates, such as pamidronate, which are potent inhibitors of osteoclastic activity. In the present study, 10 thyroid cancer patients with painful osteolytic bone metastases were administered pamidronate (90 mg, as a 2 hour intravenous infusion) monthly for 12 consecutive cycles. Bone pain, quality of life, performance status, analgesic consumption and disease staging were evaluated before and during the trial. The patients who had been administered pamidronate showed a significant decrease in bone pain (P = 0.0052). Performance status improved nearly significantly (P = 0.051), while the quality of life showed a remarkable amelioration. However, no significant decrease in analgesic consumption was recorded. Partial radiographic response of bone lesions was observed in 2/10 patients. The side effects of pamidronate were mild and transient. In conclusion, monthly infusion of pamidronate is a well-tolerated treatment that induces significant relief from bone pain and improves the quality of life of thyroid cancer patients with symptomatic and osteolytic bone metastases.