A linear surgical stapler adapted for applying a plurality of surgical fasteners to body tissue includes an anvil structure and a cartridge housing containing a plurality of surgical fasteners and a knife. The cartridge housing and anvil structure are relatively movable between a first spaced apart position and a second position in close approximation with one another. A firing mechanism is associated with the cartridge housing for ejecting the surgical fasteners from the cartridge housing to be driven against the anvil structure. The firing mechanism includes a slide bar at its distal end adjacent the cartridge housing. A lockout mechanism interacts with the cartridge housing for selective activation and deactivation. The lockout mechanism includes a lock tab that interferes with the slide bar of the firing mechanism moving the slide bar rotationally such that tabs on the slide bar move out of alignment with tabs on the knife during firing of the linear surgical stapler to prevent subsequent firing of the linear surgical stapler.
