An articulating elongate surgical instrument includes a handle assembly, an elongated body portion, a tool assembly pivotally supported on the distal end of the elongated body portion. The elongate surgical instrument includes as well an articulation mechanism to effect the movement of the tool assembly, the articulation mechanism including a pivot member operatively coupled to the tool assembly. The elongated body includes at least one articulation drive member having at least one retaining surface therein; a firing rod disposed adjacent the articulation drive, with an articulation locking actuating surface disposed upon the firing rod; and an articulation locking means configured to selectively engage and disengage from the actuating surface and to selectively engage and disengage from the retaining surface of the articulation drive member.