An engineering design theory developed for automated surgical suturing is presented. This theory is based on the operating performance of the surgeon as well as the types of needles, suture materials, and sutures used in contemporary surgical practice. As a result, the required design variables suggested include needle penetration force, needle holding jaws, types of needles, angle of needle points, and tissue types. Also presented are the medical and technical stipulations governing the design of automatic suturing devices. Finally, since a machine that ties knots is necessarily somewhat bulky, a means of avoiding surgical knots by plastic-on-plastic welding is suggested.