An electrosurgical instrument for sealing tissue includes one or more elongated shafts having an end effector assembly attached at a distal end thereof that includes a pair of opposing jaw members movable by an actuator from a first spaced apart position to a second position for grasping tissue. One or both jaw members are adapted to connect to an electrical energy source such that electrosurgical energy can be supplied to tissue disposed therebetween. A controller is coupled to the actuator for regulating a closing pressure between the jaw members and a sensor is configured to provide feedback to the controller regarding a seal pressure of tissue disposed between the jaw members.