Devices and methods are provided for less-invasive surgical treatment of cardiac valves whereby the need for a gross thoracotomy or median sternotomy is eliminated. In one aspect of the invention, a delivery system for a cardiac valve prosthesis such as an annuloplasty ring or prosthetic valve includes an elongated handle configured to extend into the heart through an intercostal space from outside of the chest cavity, and a prosthesis holder attached to the handle for releasably holding a prosthesis. The prosthesis holder is attached to the handle in such a way that the holder, prosthesis and handle have a profile with a height smaller than the width of an intercostal space when the adjacent ribs are unretracted, preferably less than about 30 mm. In a further aspect, the invention provides a method for repairing or replacing a heart valve which includes the steps of introducing a prosthesis through an intercostal space and through a penetration in a wall of the heart, and securing the prosthesis to an interior wall of the heart, wherein each step is carried out without cutting, removing, or significantly retracting the ribs or sternum.