Relapsing polychondritis (RP) with tracheobronchial involvement has a poor prognosis, and a delay in diagnosis increases morbidity and mortality; however, the diagnosis is difficult to make. Endobronchial ultrasonography (EBUS) revealed changes in the tracheobronchial cartilage in two patients who met the criteria for RP, and facilitated the diagnosis. In these cases, EBUS revealed a poorly defined bronchial wall structure with two patterns of cartilaginous damage: fragmentation and edema. These cases were successfully treated by the implantation of nitinol stents, the sizes of which were determined by EBUS. EBUS was found to be useful in the diagnosis and treatment of RP.