Lung and breast cancer can give meningeal metastases. Clinical manifestations of leptomeningeal carcinomatosis include all forms of defect of the central nervous system depending on the localization of carcinomatous foci. Diagnosis is based on the detection of carcinomatous cells by the cytological examination of the cerebrospinal fluid. Without treatment the prognosis is limited to only some weeks or months. In case the meningeal carcinomatosis is related to breast cancer, intrathecal methotrexate chemotherapy may allow a significant survival benefit and improve the quality of life in about half of the patients.