Two patients with relapsing polychondritis are described, with an analysis of forty-nine cases reviewed from the literature. The general features of recurrent inflammation of two or more cartilaginous sites (generally the ears, nose, joints, costochondral cartilages or tracheobronchial tree), when coupled with a cartilage biopsy specimen showing loss of normal basophilic staining, fragmentation, fibrous connective tissue replacement and round cell infiltration, serve to make the diagnosis. Episcleritis, diminished hearing, anemia, fever, abnormalities of myocardium and liver, and perhaps aortic insufficiency, support the diagnosis. The cartilaginous changes appear to be due to loss of chondroitin sulfate from the matrix. These acid mucopolysaccharides are recoverable in the urine during acute exacerbations. Immunofluorescent studies are presented indicating greater binding of conjugated test serum in our Cases I and II to normal human cartilage then with controls, suggesting an immune mechanism in the pathogenesis of the disease. Corticosteroid therapy remains the treatment of choice. A maintenance dose is usually necessary to suppress inflammatory activity.