A flexible annuloplasty prosthesis for repairing a heart valve having a valve annulus. The annuloplasty prosthesis comprises a flexible body defining an exterior of the prosthesis formed of a biocompatible material and configured to rest against and support the heart valve annulus upon implantation. The flexible annuloplasty prosthesis has a height of not more than 2.5 mm. This low profile characteristic enhances a surgeons ability to implant the prosthesis. In one preferred embodiment, the flexible body is a fabric material folded onto itself along a length thereof, with the annuloplasty prosthesis being characterized by an elevated longitudinal stiffness.