Fifty patients with hemibody irradiation (HBI) for metastatic bone pain have been reviewed. A total of 60 treatments were given (9 upper HBI, 31 lower HBI and 10 both upper and lower HBI). Seventeen patients had metastatic myeloma and 30 had metastatic prostatic carcinoma. The overall response rate was 83% with a 5% complete response rate. Response was seen within 24 hours in 25% of treatments and lasted until death in 74%. No difference in the response characteristics was seen between those patients with myeloma and those with prostatic carcinoma. Significant toxicity occurred in 60% of patients, predominantly gastrointestinal toxicity and bone marrow suppression. One case of fatal pneumonitis occurred. The possibility of maintaining these response rates but reducing toxicity using lower doses of HBI is discussed.