Abstract: A shoulder prosthesis, of the type comprising a humeral piece intended to be fixed in a humerus to replace at least the head thereof and comprising a hollow tubular element which must be fixed in the humerus substantially along the longitudinal axis thereof and a cylindrical rod, the upper end of which carries a ball cooperating with a glenoid bearing surface to form the shoulder joint and the lower end of which is disposed in said tubular element, this and the rod being able to slide relative to each other, the glenoid bearing surface consisting of a glenoid piece which comprises an anchoring element intended to be inserted into a cavity formed in the scapula and a female hemispherical element, this latter cooperating with the male ball of the humeral piece.