This paper is a study of the dermatologic conditions found in 500 diabetic patients of Dr. Elliott P. Joslin and Dr. F. Gorham Brigham. It was undertaken so that we might know more of the skin conditions to be expected in diabetes, and also because of the comparatively recent writings relative to the association of hyperglycemia and skin disease. It seemed reasonable to assume that we should find an abnormally high incidence of skin diseases in diabetic patients if high blood sugar has any connection between them other than coincidental, or as part of a complex of other conditions. The blood sugar average of these cases done by the Folin-Wu method was 0.19, well above the normal, whose upper limit is generally considered to be 0.11 per cent.1 Textbooks2 on diabetes mention the following skin complications as commonly present in diabetes, and generally assume these to be due