Between various functional and biochemical alterations in the platelets of atherosclerotic cases, the membrane alterations occupy an important place. The platelet intrinsic membrane protein gamma glutamyltransferase (GGT) which is involved in glutathione metabolism had decreased activity in the cases of atherosclerosis. To add new sights to the pathogenesis of atherosclerosis, GGT is characterized and correlated with other alterations. Triton X-100 solubilized membrane fractions of frozen and thawed platelets of atherosclerotic and normal subjects had 18.66 + 2.86 mU/10 9 plts and 35.67+ 3.01 mU/10 9 plts, respectively. Cholesterol, HDL- cholesterol in the membrane fractions and platelet gluathione levels were unaltered, lipid peroxidation (membrane MDA) level was increased. Keywords : Human platelets, Atherosclerosis, Gamma glutamyltransferase, Gamma glutammyl transpeptidase, Platelet membrane