Mantle cell lymphoma (MCL) is a B-cell lymphoid tumor that expresses CD20 and is associated with a poor prognosis. Central nervous system involvement has been associated with particularly dismal outcome. We report a 62-year-old male with MCL and meningeal lymphomatosis. The patient was treated with intrathecal rituximab (IT-R) 25 mg every third day for five doses with clearance of tumor after the third dose. Systemic therapy consisted of R-HyperCVAD alternating with rituximab, high-dose methotrexate, and cytarabine every 21 days, with IT-R on day 1 of each chemotherapy cycle. The patient was consolidated with an autologous stem cell transplant and remains in remission 23 months later. The use of IT-R and conventional intrathecal chemotherapy in MCLs is discussed here.