A polymer endoprosthesis is fabricated by a combination of injection molding and blow molding which form a tubular substrate of polymer material, followed by laser cutting, crimping and sterilization. After the injection and blow molding processes, a subtractive process is performed on the tubular substrate to transform it into a stent having a network of stent struts. The tubular substrate can be made in an injection mold and blow mold which are attached to each other. The transition from injection molding and blow molding can be performed while the injection molded substrate remains at a temperature at or above Tg of the polymer material.