The best kind of vascular access in patients with chronic renal failure is the arterio-venous native fistula made of patient's own vessels. Recently it has been shown that morbidity and mortality is lower in patients with native fistula than in patients with permanent catheters or with fistulas made from artificial materials. It is believed that so called ,difficult patients" exist in whom creating permanent vascular access, particularly native fistula might be difficult. The group of "difficult patients" is large and includes mainly diabetics and the elderly. In the paper the principles and causes of difficulties in creation of vascular access are presented. Recent results of our Centre concerning creation of fistulas in diabetics and the elderly are revealed. According to our experiences neither diabetes nor old age don't provide additional difficulties in creation of permanent vascular access.