Hot stamping is a method in which a steel material heated at a high temperature of 950 °C is put into a mold and simultaneously reshaped and cooled, resulting in an increase in the strength of the steel material. Since the hot stamping process allows manufacturing of lightweight and high-strength steel, it is mainly used in automobiles where fuel efficiency and safety of the drivers are major concerns. In the existing hot stamping mold cooling system, water is used as a refrigerant and it cools the system using sensible heat. When the cooling method varies from using sensible heat to latent heat, the quality of the product can be improved because the cooling performance can be enhanced and the temperature deviation of the mold surface can be reduced. In this study, by using R134a as the working fluid in the hot stamping mold cooling system, the improvement of the cooling performance was confirmed by comparing with the conventional cooling method using sensible heat. Experimental results showed that cooling performance at the refrigerant flow rate of 50 kg h-1 was 0.65 kW when using water, and 1.21 kW when using R134a. When the flow rate of the refrigerant at the mold inlet was 100 kg h-1, the cooling performance was 0.88 kW when water was used and 1.25 kW when R134a was used.