An electromechanical surgical system having an instrument housing for connecting with a shaft assembly, a shaft assembly, and an end effector. The end effector is an articulating end effector and the system includes a cable tensioning system for tensioning the articulation cables. The system includes a clutch mechanism for preventing slippage of a drive cable. The electromechanical system includes a staple cartridge that includes a knife that is movable between a raised position and a lowered position.