Chemotherapy has been used for treating chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with incosistent results. Chemotheraphy has been used for treating with inconsistent results. Rituximab is a chimeric monoclonal antibody directed against the CD20 antigen, used to treat B-cell lymphoma and reported to be effective in some neuropathies with IgM autoreactivity. We saw a 72-year-old man with CIDP refractory to steroids, plasma exchange, IV Ig, and cyclosporin. He was unable to walk; severe impairment was present also at the upper limbs. Electrodiagnostic studies revealed slowing of motor and sensory conduction velocities, and prolonged distal motor latencies. Immunoelectrophoresis evidence an IgM/k monoclonal gammopathy. Antibodies to Myelin Associated Glycoprotein (MAG) and other peripheral nerve antigens were negative. Bone marrow biopsy documented a small lymphocytic B-cell lymphoma (CD20+). Treated with Rituximab (375 mg/m2 for 4 weeks), the patient presented at follow-up evaluations (3, 6 and 8 months later) a progressive improvement. Eventually, he was able to walk, and regained full strength at upper limbs. Consistently, electrophysiological studies improved. We suggest considering treatment with Rituximab in CIDP resistant to conventional therapy, at least in cases associated with IgM lymphoproliferative diseases.