A surgical stapling apparatus, comprising: a first jaw member having a channel; a second jaw member having an anvil with staple forming depressions; a cartridge configured to selectively couple to the first jaw member, the cartridge having fasteners and a drive assembly, the drive assembly including a sled that interacts with a plurality of pushers to drive fasteners out of the cartridge; a drive member movable through the channel from a retracted to an advanced position, said drive member being configured to push the sled, whereby the sled drives the pushers (517b,518) and the pushers drive the fasteners toward the anvil as the drive member is advanced; and a lockout assembly configured to lock out the drive member to prevent misfiring thereof when a cartridge is not coupled to the first jaw member or when a spent cartridge is coupled to the first jaw member, characterized in that: said lockout assembly comprises a locking lever rotatably mounted on the first jaw member and biased toward the channel and into the locking position; and said surgical stapling apparatus further comprises an actuator in the cartridge coupled to the sled, the actuator being configured to rotate the locking lever from the channel away from the locking position when the cartridge is coupled to the first jaw member, the actuator being biased against one of said pushers, whereby movement of said one of said pushers by the sled as the drive member is advanced releases the locking lever. a first jaw member having a channel; a second jaw member having an anvil with staple forming depressions; a cartridge configured to selectively couple to the first jaw member, the cartridge having fasteners and a drive assembly, the drive assembly including a sled that interacts with a plurality of pushers to drive fasteners out of the cartridge; a drive member movable through the channel from a retracted to an advanced position, said drive member being configured to push the sled, whereby the sled drives the pushers (517b,518) and the pushers drive the fasteners toward the anvil as the drive member is advanced; and a lockout assembly configured to lock out the drive member to prevent misfiring thereof when a cartridge is not coupled to the first jaw member or when a spent cartridge is coupled to the first jaw member, characterized in that: said lockout assembly comprises a locking lever rotatably mounted on the first jaw member and biased toward the channel and into the locking position; and said surgical stapling apparatus further comprises an actuator in the cartridge coupled to the sled, the actuator being configured to rotate the locking lever from the channel away from the locking position when the cartridge is coupled to the first jaw member, the actuator being biased against one of said pushers, whereby movement of said one of said pushers by the sled as the drive member is advanced releases the locking lever. said lockout assembly comprises a locking lever rotatably mounted on the first jaw member and biased toward the channel and into the locking position; and said surgical stapling apparatus further comprises an actuator in the cartridge coupled to the sled, the actuator being configured to rotate the locking lever from the channel away from the locking position when the cartridge is coupled to the first jaw member, the actuator being biased against one of said pushers, whereby movement of said one of said pushers by the sled as the drive member is advanced releases the locking lever.