In 10 to 20% of the cases a primary failure of the arteriovenous fistulae for the chronic haemodialysis is to be observed. Therefore a modification of the operation technique after Cimino-Brescia is described. Taking its pattern from an internal ballooning of the vein by means of a Fogarty-catheter cited by Sung after application of a congestion at the upper arm an extension of the vessel by perfusion of the heparin-saline-solution is achieved. The side-to-end-anastomosing between artery and vein is done taking into consideration favourable hemodynamic conditions in a typical way. This technique is recommended analogous also in fistulae of the upper arm. During the observation time of 9 months in none of the 18 cases, which were operated in our clinic, a failure of the arteriovenous fistulae could be observed.