In order to remove the latent load, the traditional refrigerant vapor compression system (VCS), the process air is cooleddown below its dew point in order to condense out water vapor contained therein. The dehumidified air is then reheated to meet the required indoor temperature conditions. This way two loads will be added to the system. which are, (1) the energy required to bring the air from the supply temperature down to the temperature of condensation of water vapor contained in the process air (below the dew point of the air), and (2) the energy needed to reheat the air from that temperature up to the supply air temperature. The desiccant cooling can be either a perfective supplement to the traditional vapor compression air conditioning technology to attenuate the effects of its drawbacks, or an alternative to it for assuring more accessible, economical, and cleaner air conditioning. Technical and economic optimization of a hybrid-liquid desiccant cooling system is investigated in this paper. In such a system air passes through the liquid desiccant dehumidifier in the first stage and over evaporator of a vapor compression cooling system in the next stage. The liquid desiccant was recovered by using both heat rate provided by the condenser of vapor compression cooling system as well as natural gas energy. The system COP and the total annual cost (investment and operating costs) were chosen as two objective functions. The optimization was performed by using multi-objective Genetic algorithm technique. The results of modeling and optimization for our case studies (Ahvaz and Bandarabbas) with 12 hours system running per day and 6 months per year for 15 years showed that the costs of Hybrid-Descicant cooling system in Ahvaz and Bandarabbas are about 10% and 24% cheaper in comparison with vapor compression cooling system, respectively. Also, Power consumption rate is reduced 0.575 (Kw) and 0.664 (Kw) per refrigeration Ton for Ahvaz and Bandarabbas, respectively in comparison with the application of vapor compression cooling system.