An implantable prosthesis for occluding the opening of a muscle or tissue defect. The implant is laparoscopically deliverable with a system for loading and delivering the prosthesis through a trocar cannula. The prosthesis includes an implantable material with a body portion sufficient to extend across and occlude a defect opening. Antimigration barbs extend from the implantable material to prevent migration of the prosthesis after implantation. A semi-rigid ring may be attached to the material for supporting the body portion. The barbs may be located on the ring. The implantable prosthesis may be provided with a sufficient hoop strength to prevent the body portion from collapsing into the defect opening.