The optimal treatment for primary central nervous system lymphoma (PCNSL) remains undefined. In this paper, we review the main multi-institutional ongoing protocols for PCNSL. Most of the current protocols evaluate the efficacy of combination high-dose methotrexate-based chemotherapy and brain irradiation in phase II studies. Some trials focus on chemotherapy alone as initial treatment, in order to minimize long-term cognitive sequellae. Because old age appears as a major predisposing factor for combined RT and CT neurotoxicity some specific protocols have been proposed to this particular population.