In gear applications, the initiation of cracks at or near the contact surfaces of gear mates occurs mostly due to the surface contact mode of gear failure. This study aims to investigate the influence of gear materials on the contact strength of spur gears. In this study, four different gear materials are selected and the contact stress on spur gear mates is analyzed. Hertz’s contact stress equation and ANSYS 16 are used for the theoretical analysis and finite element (FE) method, respectively. The results of Hertz’s equation are compared with the results of ANSYS 16. The results show that the contact stress on spur gear mates varies when different gear materials are used in both methods. This indicates that the surface contact strength of spur gears is greatly influenced by the type of gear materials.