Computed tomography (CT) of the brain has been performed in 60 patients with breast cancer presenting with neurological symptoms suggestive of intracranial metastases, and the findings correlated with clinical features and Technetium (Tc) brain scan when available. Small size of the intracerebral metastases demonstrated by CT was clearly correlated with good clinical response to treatment, and CT was effective in detecting residual tumour. However, the varied CT appearance of intracerebral metastases did not allow differentiation from primary cerebral tumors in those patients with solitary lesions. Tc brain scan was abnormal in most patients with intracerebral metastases, but was less effective than CT in detecting multiple deposits; furthermore, skull deposits frequently made interpretation difficult. Neither test was effective in detecting meningeal infiltration. Careful CT examination of the skull overlying apparent superficial parenchymal lesions permitted the recognition of a group of patients with extradural extension of skull deposits. CT examination of brain increases diagnostic accuracy and provides important prognostic information in patients with intracranial metastases from breast cancer.