Chronic lymphocytic leukemia (CLL) rarely involves the meninges. There are few cases published in the literature. In this report, we describe a 59-year-old man with an 8-year history of CLL who presented with bone marrow involvement and cytopenias; received therapy with rituximab, fludarabine, pentostatin, and cyclophosphamide; and later went on to receive alemtuzumab. He developed leptomeningeal infiltration presenting as diplopia. The cerebrospinal fluid revealed a white blood cell count of 51/mm3; all of them were mononuclear, and the diagnosis was confirmed to be CLL by flow cytometry. A gadolinium magnetic resonance imaging scan of the head showed abnormal enhancement extending from the choroids in the left ventricle into the right ventricle, as well as changes in intensity in the splenium of the corpus callosum and left cerebellar peduncle. Whole-brain irradiation (2500 cGy) and 5 cycles of intrathecal cytarabine were administered. After this, a diffuse large B-cell lymphoma of the right testicle was discovered. An orchiectomy was performed, followed by radiation to the testicular bed. Persistent leptomeningeal involvement was treated with intrathecal methotrexate, resulting in a remission. A matched, unrelated donor bone marrow transplantation was performed.