A percutaneous heart valve prosthesis is disclosed. It comprises a valve body (2) having a valve body first end (7), a valve body second end (8) and a passage (9) extending along a longitudinal axis between said valve body first end (7) and said valve body second end (8). The valve body (2) is collapsible about said longitudinal axis for delivery via catheter. The prosthesis also comprises one or more flexible valve elements (3,4) secured to the valve body (2) and extending across said passage (9) for blocking blood flow in one direction through said passage (9) from said valve body second end (8) to said valve body first end (7). A flexible skirt (20) also extends about a periphery of said valve body (2) for blocking blood flow in said one direction between said valve body (2) and the native wall of a valve orifice in use.
