A prosthesis (10) for mitral annuloplasty, comprising an annular structure (11), in which the annular structure is composed of a flexible support segment (12), adapted to be fixed by suture along a posterior portion (PMA) of the mitral annulus (MA) which extends from the anterolateral trigone (AT) to the posteromedial trigone (PT), and of an intertrigonal rigid segment (13) interconnecting the ends (12a, 12b) of the flexible support segment. The intertrigonal rigid segment is adapted to act as a spacer between the anterolateral trigone and the posteromedial trigone. The annular structure is adapted to be fixed to the mitral annulus exclusively through the flexible support segment.
