A surgical instrument, comprising: a housing including an elongated shaft having distal and proximal portions, the proximal portion coupled to the housing, the elongated shaft defining a longitudinal axis; a stationary actuation member axially disposed within the elongated shaft, the stationary actuation member including a cam pin mechanically coupled to a distal end thereof; an actuating mechanism operably coupled to the proximal portion of the elongated shaft and moveable relative to the housing to selectively cause movement of the elongated shaft along the longitudinal axis relative to the stationary actuation member; an end effector including a pair of opposing first and second jaw members (130, 132) operably coupled about a common pivot such that at least one of the jaw members (130, 132) is movable relative to the other jaw member from a first position wherein the jaw members (130, 132) are disposed in spaced relation relative to one another to a second position wherein the jaw members (130, 132) cooperate to grasp tissue therebetween, at least one of the first and second jaw members (130, 132) including a camming slot (130c, 132c) configured to engage the cam pin to move the at least one movable jaw member between the first position and the second position upon movement of the elongated shaft along the longitudinal axis; each jaw member (130, 132) including an electrically conductive tissue sealing surface (148, 150) extending along a length thereof, each tissue sealing surface (148, 150) adapted to connect to a source of electrosurgical energy for conducting electrosurgical energy through tissue grasped therebetween to effect a tissue seal; a knife blade supported in the elongated shaft and moveable in a longitudinal direction through a knife channel defined along a length of at least one of the jaw members (130, 132) to cut tissue disposed between the jaw members (130, 132); and a switch supported by the housing and configured to be engaged by the actuating mechanism to initiate delivery of electrosurgical energy from the electrosurgical energy source to the end effector to treat tissue. a housing including an elongated shaft having distal and proximal portions, the proximal portion coupled to the housing, the elongated shaft defining a longitudinal axis; a stationary actuation member axially disposed within the elongated shaft, the stationary actuation member including a cam pin mechanically coupled to a distal end thereof; an actuating mechanism operably coupled to the proximal portion of the elongated shaft and moveable relative to the housing to selectively cause movement of the elongated shaft along the longitudinal axis relative to the stationary actuation member; an end effector including a pair of opposing first and second jaw members (130, 132) operably coupled about a common pivot such that at least one of the jaw members (130, 132) is movable relative to the other jaw member from a first position wherein the jaw members (130, 132) are disposed in spaced relation relative to one another to a second position wherein the jaw members (130, 132) cooperate to grasp tissue therebetween, at least one of the first and second jaw members (130, 132) including a camming slot (130c, 132c) configured to engage the cam pin to move the at least one movable jaw member between the first position and the second position upon movement of the elongated shaft along the longitudinal axis; each jaw member (130, 132) including an electrically conductive tissue sealing surface (148, 150) extending along a length thereof, each tissue sealing surface (148, 150) adapted to connect to a source of electrosurgical energy for conducting electrosurgical energy through tissue grasped therebetween to effect a tissue seal; a knife blade supported in the elongated shaft and moveable in a longitudinal direction through a knife channel defined along a length of at least one of the jaw members (130, 132) to cut tissue disposed between the jaw members (130, 132); and a switch supported by the housing and configured to be engaged by the actuating mechanism to initiate delivery of electrosurgical energy from the electrosurgical energy source to the end effector to treat tissue.