Expanded polytetrafluoroethylene (PTFE) has shown promise as an arterial and venous subsitute. Experimental and clinical reports on its use as a vascular prosthesis have documented excellent tissue incorporation with the development of a thin neointimal lining. We have recovered three PTFE grafts within which atheromatous changes of the neointimal were discovered on pathological examination. Anatomic location, radiographic findings, and special stains differentiated these changes from suture-line neointimal hyperplasia. Two of the three grafts were placed as angioaccess conduits for chronic hemodialysis. The potential for accelerated atherogenesis in chronic renal failure and repeated needle punctures of the grafts may have been contributory factors in these patients. These findings suggest that further evaluation is necessary to determine if PTFE allows for optimal neointimal healing or if, in fact, expanded PTFE has atherogenic potential.