Chemotherapy plus radiation therapy (RT) for primary CNS lymphoma (PCNSL) has significantly improved patient survival over RT alone, but there are late neurologic sequelae of RT, particularly in the elderly. We treated 13 patients over age 50 years (mean age 74 years) with chemotherapy alone as initial treatment for PCNSL. All received methotrexate (MTX) and procarbazine; in addition, five received thiotepa, four vincristine, and four vincristine and cytarabine. Ten achieved a complete response (CR), 2 a partial response (PR), and 1 progressed through treatment. Two patients with ocular lymphoma responded to MTX, procarbazine, and vincristine. Four of six patients who relapsed after achieving a CR or PR were treated with additional chemotherapy or RT; three achieved a CR and one a PR. Five patients remain in CR at 7.5 to 30 months, one is alive at 35 months but with progressive disease, six died of PCNSL at 5 to 30.5 months, and one died in CR of sulfur allergy 2 months after diagnosis. The Karnofsky Performance Status improved in 11 to 13 patients with treatment. Cognitive deficits were present in nine patients at diagnosis and improved in eight of these nine after chemotherapy. Only one patient developed new cognitive deficits, due to progressive tumor and possibly MTX leukoencephalopathy. Chemotherapy alone for PCNSL is effective in the elderly and eliminates the risk of RT-related neurotoxicity. RT can salvage those who relapse after chemotherapy.