Central nervous system (CNS) involvement in early (Rai Stage 0 and Stage 1) chronic lymphocytic leukemia (CLL) is rare, with only five cases reported. We present the sixth reported case, a 77-year-old male with a 4 year history of Stage 0 CLL who presented with sudden onset of diplopia and headache. Workup revealed a leukemic involvement of his CNS and he responded well to treatment with intrathecal (IT) methotrexate. After his third IT treatment, he developed a change in his mental status, consistent with a chemotherapy induced encephalopathy, which was effectively treated with IT hydrocortisone. In addition to the case presentation, we review the previously reported cases in an effort to determine any characteristics common among the Stage 0/1 CLL patients with reported CNS involvement.