Succinic oxidase activity and the incorporation rates of glucose-carbon into glycogen, lipids, lactate and carbon-dioxide were studied in vitro in samples of skeletal muscle taken from patients with peripheral arterial insufficiency.In the patients with intermittent claudication significantly increased succinic oridase activity and incorporation rates of glucose-carbon were found in muscle tissue taken from the medial head of the gastrocnemius muscle. In patients with evidence of ischaemia a t rest the metabolic activity in the muscle tissue was similar to the controls but significantly lower than in the patients with claudication on all points. K e y words: Succinic oxidase activity, skeletal muscle; [U-l%] glucose; glucose metabolism, skeletal muscle; glycogen synthesis, muscle; lipid synthesis, muscle; arterial insufficiency; skeletal muscle, human. J. Holm et al. : Muscle Metabolism in Peripheral Arterial Insufficiency Europ. J . din. Invest. 10 % 7% 65 %