Abstract: An electrosurgical instrument has a handle and a body which position and close a jaw about a tissue site for simultaneously cutting and sealing relatively large tissue structures. The jaw includes an electrosurgical cutting member, which may be a blade or wire, against which tissue is biased along a cut line, and a clamping assembly that clamps a region adjacent to or surrounding the cut line. The clamping assembly includes sealing electrodes for heating the region and welding tissue along the side of the cut as the cutter parts the tissue. The clamping assembly preferably has first and second clamping jaws extending in parallel to grip the tissue as tension is released by the cut, allowing dependable and complete sealing of the cut ends over an extended time while the tissue is immobilized.