Described are embodiments of a multilaminate or multiple layer implantable surgical graft comprising remodelable collagenous sheet material, the graft including one or more interweaving members to stitch together the graft to help prevent the layers from delaminating or separating during handling and the initial stages of remodeling. The interweaving members may comprise lines of suture, thread, individual stitches, strips of material, etc. that are woven through the layers of biomaterial in a desired pattern. In one embodiment, the interweaving members comprise a pharmacologically active substance, such as a drug, growth factors, etc. to elicit a desired biological response in the host tissue. In another embodiment, the graft further comprises a reinforcing material, such as a synthetic mesh, within the layers of remodelable biomaterial and stitched together by one or more interweaving members.