Abstract: A system for loading and unloading cargo units in refrigeration cargo ships, comprising a first elevator, which is moveable in a vertical elevator shaft internally in the ship, and a second elevator, which is moveable along the outer side of the side of the ship, together with horizontal conveyors between the elevators. An elevator shaft for the first elevator is arranged a substantial distance within the upper portion of the side of the ship, towards the midships line, to form a buffer zone or intermediate storage zone for cargo units in a region between the elevators.