A device for tensioning barbed sutures used for securing tissue or prosthetic devices includes a handle, and a shaft having a proximal end connected with the handle and a distal end remote therefrom. The distal end of the shaft includes a pressure applying surface for pressing against the tissue and the prosthetic devices. The tensioning device includes a pair of grooves extending through the shaft from the pressure applying surface at the distal end of the shaft toward the proximal end of the shaft. A barbed suture is tensioned by aligning a first section of the suture in the first groove and a second section of the suture in the second groove. After the first and second suture sections are aligned in the grooves, the proximal ends of the sections may be pulled for applying tension to the suture.