The purpose of this paper is to report the results of the first autopsy of a patient who died with acute lesions of relapsing febrile nodular nonsuppurative panniculitis. This disease is characterized by recurring attacks of fever, accompanied by the development of nodular nonsuppurative lesions of the panniculus adiposus, and healing by fibrosis leaving visible depressions in the surface of the skin if the lesions were of sufficient size. Histologic study shows necrosis of the fat cells, an interstitial exudate predominantly of lymphocytes and phagocytosis of fat both within and between the fat cells. The destroyed fat may be replaced by fibrous tissue. The autopsy observations to be reported may or may not be a part of the syndrome but will serve as a guide for future observations of patients with this as yet unusual and obscure disease. To date reports of 26 more or less typical cases of this