Patient: Male, 68 Final Diagnosis: Chronic lymphocytic leukemia Symptoms: Arthritis Medication: - Clinical Procedure: - Specialty: Oncology Objective: Rare co-existance of disease or pathology Background: Chronic lymphocytic leukemia (CLL) is the most common leukemia affecting older adults. As such, many of these patients suffer from co-existing disease states, and the provider must take these comorbidities into account when determining a treatment regimen. The widespread use of monoclonal antibodies (mAbs) has drastically changed the treatment landscape of multiple diseases, ranging from leukemia to autoimmune conditions such as rheumatoid arthritis. Case Report: We present the case of a patient who had progression of his CLL and rheumatoid symptoms on rituximab therapy, and was subsequently treated with the second-generation anti-CD20 antibody obinutuzumab. Obinutuzumab therapy was associated with simultaneous sustained remission of both disease states, allowing for discontinuation of all other disease-modifying anti-rheumatic drugs (DMARDs), and prolonged remission of his CLL. Conclusions: While anti-CD20 antibodies have a clear role in the treatment of leukemia and inflammatory conditions, the success of obinutuzumab in RA has not been fully evaluated. We present this case as further evidence of the strong role of anti-CD 20 therapy in multiple conditions, and the unique opportunity for control of simultaneous disease states through targeted inhibition of shared common pathways.