The patient with end-stage renal failure is largely dependent upon hemodialysis for survival (Yang and Humphrey, 2000). Adequate care of these patients requires vascular access that delivers a flow rate adequate for the dialysis perception, has a good long term patency and is associated with a low complication rate (Murphy et al., 2000).Permanent vascular access should be easily accessible and suitable for undisturbed, long term use. This is generally obtained by an arteriovenous (AV) fistula. By a synthetic AV fistula (AV graft) or by double lumen, cuffed tunneled catheters (Schwab and Beathard, 1999).Blood flow imaging using colour Doppler has proven effective in predicting graft failures in hemodialysis patients (Kim et al., 2001). It will allow an understanding of the pathology in non-functioning fistulae or the cause of complications that develop secondarily (Mahmutyazicioglu et al., 1997).Doppler ultrasound techniques are accurate, sensitive and non-invasive methods. It is available in most hospitals. The equipment is less expensive, requiring fewer personnel and less demanding facilities than angiography (Geitung et al., 1996)Complications associated with hemodialysis vascular access represent one of the most important sources of morbidity among end-stage renal disease patients (Hirth et al., 1996).The aim of this study is to evaluate the role and usefulness of colour Doppler flow imaging by using gray-scale, peak systolic velocity, end-diastolic velocity, resistivity index and volume of blood flow in patients with an intermediate probability of access dysfunction on the basis of clinical findings or symptoms suggestive of hemodialysis access malfunction.