We report on two patients (one female 42 years, one male 47 years) suffering from insulin-dependent diabetes mellitus (IDDM) for more than 20 years. Both patients exhibited sclerodactyly and sclerosis of the hands and lower arms as well as swelling and slight contracture of the distal interphalangeal joints. Interestingly, internal organs were not involved and autoantibodies characteristic for scleroderma were missing. Poor utilization and excess of glucose seem to be responsible for the activation of fibroblasts to produce abundant matrix proteins in the skin. Significant therapeutic improvement of the glucose metabolism was able to improve joint contractures or at least to stop the progression of skin changes in our patients. These skin changes should not be misdiagnosed as systemic sclerosis.