A prosthesis for the treatment of hernias and/or laparoceles via an intraperitoneal route, having a mesh of filaments of non-resorbable and biocompatible polymer material having interstices permitting tissue growth and a sheet of polymer material having barrier properties and low adhesion to sensitive organs and tissues. The sheet is superimposed upon and joined to the mesh so as to form a stratified structure. In particular, the sheet is joined to mesh through a plurality of filaments located alongside each other at a spacing of not more than 5 mm. Each filament has a plurality of attachment sites to the mesh which are not more than 15 mm apart, and each length of filament between two successive attachment sites projects from the surface of the mesh facing sheet and is fused to the sheet.
