A magazine loader/unloader, designed to stand on a table or be handheld during use, includes a loader/unloader housing, including right and left sides, front and rear sides, and a flat bottom plate; a loading structure, including a loading member; and an unloading structure, including top and bottom guides, and an unloading protrusion. Also disclosed is a method of using the magazine loader/unloader, including positioning cartridge, loading cartridge, and unloading cartridge.