A surgical cutting and fastening instrument is disclosed. According to various embodiments, the instrument may include a handle assembly that has an elongate shaft attached thereto. An end effector that is configured to support a staple cartridge may be pivotally coupled to the elongate shaft. The handle assembly may support a generator of rotary motion that interfaces with a rotary drive system that may include a flexible drive shaft. The flexible drive shaft may be configured to impart a driving motion to a knife supporting assembly supported within the end effector. Such arrangement enables the end effector to be fired while being articulated relative to the elongate shaft.
