A loading unit (200) configured for engagement with a surgical instrument (100) is disclosed. The loading unit comprises a proximal body portion (210) and a tool assembly (220). The proximal body portion defines a longitudinal axis. The tool assembly is disposed in mechanical cooperation with the proximal body portion and includes a cartridge assembly (400) and an anvil assembly (300). At least one of the cartridge assembly and the anvil assembly is movable with respect to the other between an open position and an approximated position to engage tissue therebetween. The cartridge assembly is configured to house a plurality of fasteners (600) therein. The diameter of the tool assembly is less than or equal to about 8 mm.
