This research presents the results of calculating the disposal cost efficiency for the four disposal alternatives for the CANDU spent fuel that are under development in Korea currently. The KRS-1 alternative, developed first, was set as the standard, and the efficiency of the KRS-1 alternative was assumed to be 100%. The cost calculation result shows that the A-KRS-22, which was developed most recently among the CANDU spent fuel disposal alternatives, manifested -61.7%, -45.7%, -47.0%, -78.9% and 61.7% when compared to the KRS-1 alternative concerning disposal tunnel excavation, disposal hole excavation, bentonite, disposal canister and backfilling. Moreover, the cost calculation method for the dominant cost driver that uses the unit disposal module concept for the calculation of cost efficiency was used. As for the reason that the standard for efficiency measurement was taken per each bundle, it is because the amount of bundle capacity concerning the spent fuel differs by disposal canister. (C) 2011 Elsevier Ltd. All rights reserved.