Light microscopic and for the first time electron microscopic (EM) studies of involved elastic ear cartilage in a patient with relapsing polychondritis confirm the superficial location of the inflammatory reaction. EM studies of deep cartilage were identical to those on controls except for a rare necrotic cell. Superficial cartilage showed a finely granular electron-dense material. This material, which may be protein, possibly of enzyme or immunoglobulin origin, also surrounded some elastic fibrils. Findings of predominantly superficial changes and the multisystem disease in the present patient and in many others suggest that the cartilage destruction is part of a systemic inflammatory disease.