An orthotopic artificial bladder endoprosthesis comprises a casing (2) made of a PGA fiber fabric; said casing (2) having two first connectors (3) for the connection with the ureters of a patient and a further connector (4) for the connection with the urethra of a patient; an inflatable element (5) inserted in said casing (2); said inflatable element (5) being switchable between an inflated configuration, in which it supports and maintains in position the casing (2), and a deflated configuration.