A surgical stapling instrument, comprising: a handle comprising a trigger; a shaft extending distally from said handle; a firing member operably coupled with said trigger such that a firing motion can be transferred from said trigger to said firing member to move said firing member along a firing path; a first staple cartridge positioned within said shaft, wherein said first staple cartridge comprises: a first cartridge body comprising a plurality of first apertures; and a plurality of first staples each comprising at least one first staple leg positioned in a said first aperture, wherein said first staple legs are slidable within said first apertures, and wherein said first staple legs comprise a first length; a second staple cartridge positioned within said shaft, wherein said second staple cartridge comprises: a second cartridge body comprising a plurality of second apertures; and a plurality of second staples each comprising at least one second staple leg positioned in a said second aperture, wherein said second staple legs are slidable within said second apertures a first jaw comprising a channel configured to receive said staple cartridges, a second jaw comprising an anvil configured to deform said staples; and a cartridge driver configured to sequentially advance said first and second staple cartridges into said channel from a staging position, and characterized in that said second staple legs comprise a second length which is different than said first length. a handle comprising a trigger; a shaft extending distally from said handle; a firing member operably coupled with said trigger such that a firing motion can be transferred from said trigger to said firing member to move said firing member along a firing path; a first staple cartridge positioned within said shaft, wherein said first staple cartridge comprises: a first cartridge body comprising a plurality of first apertures; and a plurality of first staples each comprising at least one first staple leg positioned in a said first aperture, wherein said first staple legs are slidable within said first apertures, and wherein said first staple legs comprise a first length; a first cartridge body comprising a plurality of first apertures; and a plurality of first staples each comprising at least one first staple leg positioned in a said first aperture, wherein said first staple legs are slidable within said first apertures, and wherein said first staple legs comprise a first length; a second staple cartridge positioned within said shaft, wherein said second staple cartridge comprises: a second cartridge body comprising a plurality of second apertures; and a plurality of second staples each comprising at least one second staple leg positioned in a said second aperture, wherein said second staple legs are slidable within said second apertures a second cartridge body comprising a plurality of second apertures; and a plurality of second staples each comprising at least one second staple leg positioned in a said second aperture, wherein said second staple legs are slidable within said second apertures a first jaw comprising a channel configured to receive said staple cartridges, a second jaw comprising an anvil configured to deform said staples; and a cartridge driver configured to sequentially advance said first and second staple cartridges into said channel from a staging position, and characterized in that said second staple legs comprise a second length which is different than said first length.