Hemodialysis patients are characterized by endothelial dysfunction, which is the early initiating event in atherosclerosis. Kidney transplantation improves patient's survival and quality of life. Besides that, kidney transplantation improves the cardiovascular outcome of patients receiving hemodialysis. Aim of the study was to investigate whether or not kidney transplantation improves endothelial function in adult chronic hemodialysis patients Patients and Methods In this study, we included 25 hemodialysis patients who have not been characterised by atherosclerotic complication (group 1) and 20 healthy people as a control (group 2). Patients with history of myocardial infarction or stroke or peripheral arterial disease and showing abnormal results in their electrocardiography or echocardiography were not been included. In a first week, before kidney transplantation, endothelial function of patients were measured by a technique described by Celermajer et all. In this technique, flow mediated dilatation (FMD) and glyceride trinitrate mediated dilatation of brachial artery are measured by experienced radiologist with ultrasonography. Same measurements were also done in group 2. Endothelial function of group1 were restudied on the 7thday after succesfull kidney tansplantation Results There was no difference in age and gender distribution between group 1 (n=25, mean age: 33.1±8.1year, male/female: 15/10) and group 2 (n=20, mean age: 34.5±6.5 year, male/female: 11/9, p>0.05). Etiology of end stage renal disease was obstructive nephropathy (n=6), chronic glomerulonephritis (n=8), hypertensive nephrosclerosis(n=4) and unknown(n=7).All of the patients had been dialysed three times in a week until kidney transplantation. Average duration of dialysis was 4hr/session. Mean creatinine value of hemodialysis patients was 7.0±1.5mg/dl. Before kidney transplantation, FMD of brachial artery in hemodialysis patients was 6.6±3.4 %, after succesfull kidney transplantation, FMD of brachial artery in these patients was 10.6±3.1% the 7th day of transplantation (p<0.001). Glyceride trinitrate mediated dilatation before and after kidney transplantation were not different (16.9±7.0 % vs18.3±4.6 %, p<0.05). FMD of brachial artery in controls were found better than transplant patients (10.6±3.1vs13±3.9, p<0.05). Cardiovascular events, in which atherosclerosis commonly contributes, are the main reason for the mortality in hemodialysis patients. This is the first study showing that succesfull kidney transplantation improves endothelial dysfunction described by non-invasive method in adult chronic hemodialysis patients.