The paper presented a comparison of fuel costs between COGES and Diesel-electric propulsion systems for large conventional cruise ship. COGES propulsion system installed on the analyzed cruise ship saves ship’s space in comparison with Diesel-electric propulsion system. Diesel-electric propulsion system uses much more fuel for additional steam production and therefore, the additional fuel costs of this propulsion system are much higher in comparison with COGES system. Net profit of 50 additional cabins cannot compensate the difference in COGES system total annual fuel costs throughout the observed time period when compared to Diesel-electric propulsion system. The COGES propulsion system has much lower exhaust gas emissions in comparison with equivalent Diesel-electric system and therefore, in presented comparison, COGES could become profitable in the future if the emission regulations become more rigorous.