Glycosaminoglycan composition of normal saphenous veins and atherosclerotic saphenous vein grafts is reported. Dermatan sulfate is the main glycosaminoglycan present in both normal saphenous veins and saphenous vein grafts. These tissues also contain chondroitin sulfate and heparan sulfate. Although the total amount of glycosaminoglycans decreased in the grafts (compared with normal saphenous veins), the grafts showed an increase in the relative amounts of dermatan sulfate and chondroitin sulfate. Heparan sulfate was decreased, compared with normal controls. These findings suggest the involvement of blood vessel glycosaminoglycans (not only the arterial glycosaminoglycans) in the process of atherosclerosis.