DIN 41Cr4 and DIN 42CrMo4 materials have been widely used in automotive driving elements. Although 42CrMo4 is more expensive than 41Cr4, it is more preferable in terms of material properties. In this study, these two materials were heat treated by austenitizing in a continuous furnace at 850 degrees C and quenched in oil at 90 degrees C. After they were tempered at various temperatures, mechanical properties were determined for each tempering temperature. The material properties for both materials were compared with each other. Results indicated that same mechanical properties for 41Cr4 and 42CrMo4 can be achieved by tempering 41Cr4 about 50 degrees C lower temperature than for 42CrMo4. In addition to the mechanical tests, fatigue tests were performed for both materials. Weibull distributions were plotted. Results indicated that 42CrMo4 had a longer life than 41Cr4 material.