A well-functioning vuscular access is very important for achieving adequate dialysis and maintaining good quality of life in hemodialysis patients. Primary failure of arteriovenous fistula (AVF) is defined as unsuccessful fistula utilization for at least 6 consecutive dialysis sessions. Furthermore, secondary fistula failure is defined as unsuccessful utilization of fistula even though the initial fistula function is normal. Thus, it is vital to identify the risk factors which may contribute to primary and secondary failure of AVF so as to improve the function of AVF as early as possible.