We treated 183 patients who had brain metastases with whole-brain radiation therapy (RT) and adrenocortico- steroids utilizing a new high-dose radiation protocol. Treatment produced neurological improvement in 135 patients (74%); there was no change in 37 (20%), and deterioration occurred i n l l (6%). Of those patients who improved, two-thirds maintained neurological improvement for the remainder of their lives or for at least nine months, and one-third relapsed. One-third of those who relapsed improved again with steroids or further RT. Clinical improvement paralleled tumor regression on CT scan. Despite the clinical response, median survival was only twelve weeks; 24% lived six months and 8% lived one year. Death resulted from progressive brain disease in 16% of the patients. Two-thirds of the patients died of advancing systemic disease in the setting of stable, improved neurological function. These data suggest that the majority of patients with brain metastases benefit from RT and that systemic cancer, not central nervous system disease, limits the length of life.