Several biodegradable and artificial materials have been used in the urinary tract for partial or total replacement of the bladder. Most of the graft materials have resulted in stone formation, collapse, rejection, or extrusion of the graft without adequate reconstruction of a functional bladder. In this paper, we present our assessment of the use of placental membranes as a feasible, economic, and acceptable organic agent for bladder reconstruction. Eight mongrel dogs were subjected to supratrigonal cystectomy, and then a 10 X 10 centimeter patch of human placental membrane was sutured to the remaining trigone in a watertight fashion. The dogs were sacrificed twelve weeks after surgery. Histologic examinations revealed evidence of regeneration of normal-appearing smooth muscle along the path of a retracting placental patch, and thus of reconstitution of a normal-appearing and functioning bladder. On the basis of this study, we believe that placental membranes, because of their low antigenic properties and easy availability, provide an excellent graft material for the urinary tract. Further studies concerning the application of this graft material in various pathological conditions are now in progress.