The glucose utilization by different skeletal muscle tissues of short-term streptozotocin treated Wistar rats was studied both in vivo and in vitro. The findings permit the following statements: The reduced metabolic conversion of glucose is mainly the result of the diminished transport of glucose into the muscle cells. The utilization of the glucose taken up by the muscle cells for synthesis of glycogen is unchanged in the diabetic animals and can be stimulated by insulin correspondingly as in normal rats. The conversion of the glucose metabolized by the cells to lactate and the time course of the specific activity of glycogen and lactate lead to the conclusion that glycogenolysis in the muscles of streptozotocin diabetic rats during the incubation is enhanced.