Twenty-five breast cancer patients with meningeal carcinomatosis seen over a period of 16 months were reviewed. In all cases, the clinical diagnosis was made in the presence of diverse neurological manifestations by the demonstration of malignant cells in the cerebrospinal fluid. In ten patients, the clinical diagnosis was documented at autopsy. All patients were receiving systemic chemotherapy at the time the diagnosis of meningeal carcinomatosis was made. In 9 of the 25 patients, meningeal involvement was associated with progression of systemic metastases, while 5 exhibited stable or partial remission from systemic metastases and 7 were in complete remission at the time of their CNS relapse. CNS involvement was the first manifestation of recurrent disease from breast cancer in 4 of 25 patients. Meningeal involvement can, therefore, occur at any time during the course of breast cancer. With increasing diagnostic awareness and the employment of several therapeutic strategies, the prognosis of these patients, though poor, was significantly improved over that of historical control patients.