A self contained gas powered endoscopic surgical apparatus is provided for placing lateral lines of surgical fasteners into body tissue. The apparatus includes a frame portion, an elongated portion extending from the frame portion, and an articulating fastener applying assembly associated with a distal end of the elongated portion. The fastener applying assembly includes a base portion, a staple cartridge housing, and an anvil member which has a forming surface thereon against which surgical fasteners are driven as they are ejected from the cartridge housing. A self contained pneumatic system is associated with the frame portion and is actuable to eject the surgical fasteners from the cartridge assembly. A first mechanism is provided for effectuating the rotation of the fastener applying assembly about an axis defined by the body portion, a second mechanism is provided for effectuating the articulation of the fastener applying assembly, and a third mechanism is provided for independently rotating the cartridge housing and anvil member relative to a longitudinal axis defined by the base position to increase the range of operability of the apparatus.