Based on existing experimental and clinical observations the expanded PTFE graft shows convincing advantages in some indication fields (e.g., vascular access for hemodialysis, venous reconstruction) compared with conventional porous prostheses and biografts. On the other hand, we have to realize that expanded PTFE is not yet qualified to be the optimal substitute for small arteries. In spite of encouraging preliminary results, the use of this new type of vascular prosthesis still requires critical evaluation to avoid unpredictable failure due to uncritical surgical optimism (caution: Sparks disaster!). Further improvements may be expected from a better anchorage in the surrounding tissue (e.g., external velour), and from an increase of antithrombogenity of the inner surface.