Introduction. - The authors report a case of neurologic manifestations revealing Richter's syndrome in chronic lymphocytic leukemia. Exegesis. - Cranial nerve palsies were the initial manifestation of the disease. Computed tomography and magnetic resonance imaging were normal. Cerebrospinal fluid analysis with alkaline phosphatase-antialkaline phosphatase revealed the existence of a large-cell lymphoma. Conclusions. - Clinical aspects of this unusual localization of Richter's syndrome are reviewed. (C) 1999 Elsevier, Paris.