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 of the firing mechanism by disconnecting the distal end of the slide bar from a component housed within the cartridge housing.