PURPOSE: Failure of hemodialysis access is the main medical problem in chronic renal failure patients. This resulted from complications such as thrombosis, infection, pseudoaneurysm, steal syndrome and so on. This study was undertaken in an attempt to describe the clinical characteristics and significances of dialysis failure due to iatrogenic fistula between prosthetic graft and native vein at puncture site. METHODS: During 5 years between Feb. 2005 and Feb. 2009, five Iatrogenic fistulas were identified in a retrospective review of 133 patients performed 220 times fistulography due to dialysis failure in PTFE (polytetrafluoroethylene) graft. RESULTS: Overall incidence is 3.8 % in PTFE graft cases. Mean age is 50 (28~75) years, male to female ratio 2:3. Median 1st patency period is 20 months (6~36). All iatrogenic fistula is usually located in not venous but arterial limb of forearm loop, combined with the stenosis in venous limb and anastomosis site. More than 70% venous anastmotic stenosis in 4 cases (80%) and diffuse stenosis of venous limb in 3 cases (60%), revised concomitantly either by patch angioplasty or ballooning. Medial follow-up period is 8 months (5~12), graft occlusion occurred in one case. CONCLUSION: All iatrogenic fistula usually occurs in not venous but arterial limb of forearm loop graft. Most iatrogenic fistula is combined with the stenosis in venous limb and anastomosis sites, must be revised concomitantly either by patch angioplasty or ballooning. Close assessment to superficial vein and graft is needed for early detection. Fistulography is the most useful diagnostic tool. Careful cannulation method is required to prevent the occurrence of iatrogenic fistula in chronic renal failure patients.