This is a report of eight cases of scleredema associated with diabetes mellitus. There were six men and two women, with ages ranging from 41 to 80 years. The predominant clinical features were obesity, long-standing diabetes mellitus, and scleredema; there was a high incidence of heart disease. Five patients had diabetic retinopathy. Six were maturity-onset, overt diabetics while two were chemical or latent diabetics. Most patients were resistant to antidiabetic therapy. On skin biopsies the dermis was about three times thicker than normal. Histologically there was a marked, benign hyperplasia of collagen fibers involving the dermis and subcutaneous tissue. Chemical analysis of the skin revealed an increase in collagen and glycosaminoglycans, proportional to the increase in skin thickness. Analysis of the glycosaminoglycans revealed both hyaluronic acid and dermatan sulfate.