A retrospective study was undertaken of factors affecting survival in 129 patients with cerebral metastases from malignant melanoma referred to the Department of Radiation Oncology from June 1982 to January 1990. Their ages ranged from 19 to 83 years and the time interval from diagnosis of the primary tumour to development of cerebral metastases ranged from one month to 17 years. Cerebral metastases were apparently solitary in 59 (46%) and multiple in 70 (54%) patients respectively. Craniotomy with resection of tumour was performed in 49 patients, of whom 24 had a solitary cerebral metastasis as the only evidence of disease. Most patients (94%) received a course of radiotherapy. Median survival of the whole group after detection of cerebral metastases was 5 months (range less than 1-87+). Univariate analysis indicated that a solitary cerebral metastasis, absence of extracranial disease and tumour resection predicted improved survival, but only surgical intervention was of independent prognostic significance in a multivariate analysis. The effect of cranial irradiation on survival could not be assessed, but the dose of radiation did not influence survival. Of the 10 patients who survived for more than 2 years, eight had total resection of a solitary cerebral metastasis.