The implantable reinforcement prosthesis, in particular for reinforcing the abdominal wall, comprises a reinforcement part (10) forming a netting intended to be incorporated into the inner surface of the wall (1) in order to reinforce said wall and a plurality of flat strips (20; 120) made from textile material extending from the edges of the reinforcement part and intended to be placed in transfixing penetration in the wall to each side of the area to be reinforced. According to a particular provision, the strips (20; 120) comprise anchoring wires (30; 130) intcorporated by interleaving into said strips, and extending along the length of said strips. The strips can be formed from two different segments of strips, depending on the region of the wall in which they are to be positioned.