Monitoring of vascular access is essential for clinical evaluation on hemodialysis patients, detects early disfunction of access, allows adequate dialysis and decreases the morbidity associated. Although is demonstrated that intra-access pressure (IAP) is a good method of screening to evaluate arterial-venous (AV) fistulas, its utility is uncommon because its measurement requires a complex system. We would like to validate the utility of IAP monitoring using a simplified measure of IAP and its relation with other methods of screening in detecting stenoses prior to thromboses of AV grafts. We studied 24 AV grafts of 24 patients during 18 months we measured arterial pressure, mean arterial pressure (MAP), dynamic venous pressure, IAP, Kt/v, URR, recirculation index (RI), access flow and color Doppler flow, dividing the patients in two groups, with stenoses or not, if IAP/MAP > 0.5 and stenoses > 0.50 by Doppler we performed arteriography and percutaneous transluminal angioplasty with stent if stenoses exits. The values of IAP, MAP, RI were higher significantly in the stenoses group with increase of vascular access in grafts were dilation by angioplasty was made. All stenoses detected with IAP were confirmed by Doppler and arteriography but one. We conclude that IAP is an early, useful, easy, effective method in detecting stenoses of AV grafts prior to thrombosis.