Mesothelioma is a disease mostly involving the pleura, peritoneum, and pericardium. Hematogenously disseminated metastases involving the liver, adrenal glands, kidneys, and contralateral lung have been documented in some patients, but central nervous system (CNS) involvement, especially as leptomeningeal infiltration, is very rare. A 44-yr-old mesothelioma patient admitted to hospital with convulsions and diffuse leptomeningeal infiltration was shown with magnetic resonance imaging. She had a positive history for environmental asbestos exposure. Pleural and axillary lymph node biopsies were consistent with mesothelioma. Diffuse leptomeningeal infiltration is the only constant radiological finding reported as a diagnostic criteria for CNS involvement and histopathological confirmation is usually possible only at autopsy, so clinical and radiological diagnosis is essential after exclusion of other possible causes.