A method is provided for pre-stretching implantable biocompatible materials, such as material to be incorporated into an implantable device. A sheet of implantable biocompatible material is attached to one or more tensioning members, where tension is applied along one or more axes. Tension is applied for a period of time, and at an appropriate force, to produce a desired degree of thinning or pre-stretching of the implantable biocompatible material. During the tensioning, the implantable biocompatible material is maintained at an elevated temperature, such as a temperature that is at least substantially a temperature of an environment into which the material will be implanted.
