A caulking gun cartridge caddy has back to back cartridge clamps which surround a portion of the circumference of two caulking gun cartridges, holding them in parallel juxtaposition whereby one cartridge is held in readiness for replacing another while the latter is in use. The caddy holds the cartridges oriented in opposite directions to minimize interference by the spare cartridge with using the caulking gun. The caddy may include means on its side for also holding a smoothing tool commonly needed by users to smooth a bead of the fill material after it has been distributed from the cartridge nozzle.