A surgical cutting and fastening instrument (10). The instrument (10) comprises an end effector (12), a shaft (8) connected to the end effector (12), and a handle (6) connected to the shaft (8). The handle (6) comprises an electric, DC motor (65) connected to a drive train in the shaft (8) for powering the drive train. The handle (6) also comprises a power pack (299) that comprises at least one charge-accumulating device connected to the DC motor (65) for powering the DC motor (65).