Relapsing polychondritis (RP) is a rare, progressive immune-mediated systemic inflammatory disease of unknown etiology, characterized by recurrent inflammation of cartilaginous structures. Approximately 30% of RP cases are associated with other autoimmune diseases. However, the co-occurrence of RP and Crohn disease (CD) has rarely been reported. Herein, we present a 35-year-old woman diagnosed with RP and CD, who was refractory to initial conventional medications, including azathioprine and glucocorticoid, but who subsequently responded to infliximab (IFX). For both diseases, remission was sustained with IFX. There has been no previous report regarding the successful treatment of co-existing RP and CD with IFX.