The authors report 33 patients with primary central nervous system lymphoma (PCNSL) treated from 1989 to 1995. There were 19 males and 14 females. Median age was 46 years(range: 4-74). Patients were symptomatic for a median of 3.5 weeks. Headache was the most common complaint. Median Karnofsky performance score(KPS) at admission was 70. Twenty-eight of 33 patients had solitary PCNSL and 5 had multiple deposits. Lesion was confined to the supratentorium in 26 patients, 4 in cerebellum, 3 in intra- and extradural spinal cord and 1 in orbit. All patients except two who refused further treatments received whole brain and/or spinal irradiation with or without supplemental tumor boost. Radiation therapy(RT) without systemic chemotherapy was introduced in 17 patients. Systemic chemotherapy was introduced to 13 patients and additional intrathecal chemotherapy in 10 among 13 patients. After follow-up periods ranging from 2 to 70 months, median overall survival period was 56 months in patients treated with RT only and 43 months in those with RT plus systemic chemotherapy(p=0.37). Median progression-free survival period was 48 months in RT group and 21 months in RT plus Chemo group(p=0.05). All 4 patients with intermediate grade PCNSL are still alive: One patient with diffuse small cleaved subtype survived complete response at 41 months and 3 patients with diffuse mixed subtype also survived without recurrence at 25, 51 and 62 months. Median progression-free and overall survival for diffuse large cell subtype(high grade) was 36 and 51 months, respectively. This study proved that it was the histopathologic grade that has exerted a considerable influence on survival period and other variables were not significant factors to overall survival period.