Malignant CNS lymphoma is a malignant intracranial tumor and in most cases they run a fulminating course if left untreated, with 3 to 5 months survival after appearance of the initial symptoms. Sixteen patients with malignant lymphoma were treated in Asan Medical Center from 1989 to 1994. All patients were underwent tissue diagnosis with subtotal resection or stereotactic biopsy and followed by cranial or craniospinal irradiation with or without systemic chemotherapy. One and three year survival rate of the patients was 88% and 78% respectively. In conclusion, addition of chemotherapy and/or cranial radiation for treatment of the CNS lymphoma may improve survival.