Objective: To assess the efficacy and toxicity of rhenium-186 HEDP in treating metastases. Patients: Twenty-six patients with bone pain from metastatic cancer were treated with 35 mCi of <sup>186</sup>Re HEDP administered intravenously in the outpatient clinic. Methods: Patients were followed with pain diaries, records of medication, morbidity, sleep patterns, serial bone scans and a Karnofsky index. Twenty-five patients with complete records were evaluated. Patients were grouped according to the extent of bone metastases as seen in the bone scans. Results: Sixteen patients (64%) showed clinical responses of which 4 became completely pain-free. Pain relief typically began 10–20 days after <sup>186</sup>Re HEDP was administered, while maximum benefit was normally achieved by 6 weeks. Relief of pain was maintained for 4–15 months (mean 6 months). No immediate adverse reactions were observed following the administration of <sup>186</sup>Re HEDP. Only a mild transient fall in platelet levels was noted, which normalized by 6 weeks. Conclusion: <sup>186</sup>RE HEDP appears as a safe, convenient and an effective palliative for pain secondary to bone metastases in cancer patients.