A surgical stapling device having a handle assembly, an elongated body portion, a shell assembly housing a plurality of staples and an anvil assembly movable relative to the shell assembly. An approximation mechanism is movable from a first position to a second position to move the anvil assembly relative to the shell assembly between a spaced position and an approximated position. A firing mechanism for advancing the staples is actuable when the approximation assembly is in the second position and the anvil assembly is in the approximated position. A lockout mechanism operatively associated with the approximation mechanism is movable from a non-blocking position to a blocking position, wherein in the non-blocking position the approximation mechanism is movable from the first position to the second position and in the blocking position movement of the approximation mechanism from the second position to the first position is prevented.