A sub-miniature surgical staple cartridge includes an elongated housing having longitudinally extending strips forming walls with a wall thickness preferably less than 0.015 inch. The walls define a plurality of longitudinally spaced pockets which receive a corresponding plurality of U-shaped surgical staples above generally flat corresponding drivers. The thin walls are formed of sheet metal or extruded plastics material or heat-formed sheet plastics material with the outer side walls having opposite end walls welded together or integrally connected. The outer side walls may be sheet metal enclosing sheet metal or plastic extruded internal walls, or the entire cartridge may be extruded of a plastics material or formed of sheet plastics material and have a plastic bottom wall.