A 69-year-old female patient was treated for primary CNS-lymphoma (PCNSL) starting from August 2002. As her general condition allowed no high-dose methotrexate (MTX) therapy, radiotherapy was administered as a first-line treatment. CSF involvement could be managed by intrathecal Ara-C. Her general condition and cognitive status stabilized, but did not improve for 3 months. Therefore, oral chemotherapy with Temozolomide 200 mg/m2 was initiated. After two courses, which were tolerated without any problems, the patient's Karnofsky performance index had improved from 40% to 50%, the Mini-Mental Status rose from 16 to 27/30. The CSF-cell count was elevated again to 23 cells/l without signs of meningeal relapse. Unfortunately, the patient died unexpectedly from suspected pulmonary embolism. We conclude that adjuvant Temozolomide chemotherapy can improve the general condition and cognition in patients with PCNSL even when the general condition is poor. Long-term effects and neurotoxicity remain to be analysed in prospective trials, as well as the efficacy in leptomeningeal disease.