Fifty-five patients with diffuse pain due to bone metastases from prostate carcinoma were treated by pituitary ablation (53 with intrasellar Yttrium 90 and 2 with intrapituitary alcohol instillation). The provisional criteria of the British Prostate Group were used to assess results. Post-operatively, 44 patients (80%) were significantly free of pain and 12 of them were completely pain-free. In only 11 cases (20%) was there no relief of pain. Of the 39 patients who required narcotics before ablation, only 12 required them post-operatively. Pituitary ablation with Yttrium 90 has an important place in the relief of pain in advanced carcinoma of the prostate, although survival is not increased.