Increasing the amount of carbon and alloy elements in steels causes reduction in the start and finish temperatures of martensitic transformation. Therefore, in steels with high carbon and alloy elements, the finish temperature of martensitic transformation decreases to lower than 0°C. After usual heat treatment of quenching and tempering, some austenite will remain in steel structure. The presence of austenite causes reduction in hardness, wear resistance and dimensional stability of steels. Thus, one of the major challenges in the heat treatment of these steels is minimizing or eliminating the amount of retained austenite. One of the methods can be used for this purpose is deep cryogenic treatment. After performing usual heat treatment on H13 tool steel, some austenite will remain in structure. Considering the widespread usage of this steel, it seems to be necessary to use deep cryogenic treatment in order to reduce the amount of retained austenite. In this study, using metallography and optical microscopy, the effect of keeping samples in -196°C for 24, 48 and72 hours, respectively, was investigated. In addition, the amount of hardness and wear resistance was studied using hardness tests and wearing tests and finally wearing mechanism was studied using electron microscopy. After quenching and tempering, the amount of retained austenite was about 7%, while this percentage decreases to lower than 1% after deep cryogenic treatment for 72 hours. Results indicated that the mechanical properties such as hardness and wear resistance increases after keeping samples in -196°C for 72 hours as 8% and 43%, respectively. The increase in mechanical properties was due to reduction in the amount of retained austenite and etha carbides precipitation in microstructure. Evaluation of wear surfaces and debris particles caused revealed that in usual heat treatment of quench and temper the dominant mechanism was extreme adhesive wear and in deep cryogenic treatment the dominant mechanism was weak adhesive wear and tribochemical. Key words deep cryogenic treatment, H13 tool steel, wear behavior, retained austenite