Five cases of sclerosing fibrosis, each affecting a different organ or system or a combination of systems, are described to illustrate the concept that these are different manifestations of a common process having perhaps a systemic etiologic basis. We feel that the terms "sclerosing fibrosis" and "multifocal fibrosclerosis" are more appropriate designations than the various terms adopted in the past, which have very limited topographic application, i.e. "sclerosing mediastinitis," etc. The characteristic pertinent radiologic and pathologic features are discussed. Differentiation from malignant tumors and the importance of early diagnosis are stressed because of the effective therapeutic response to the use of steroids in this condition.