In this study, the microstructure, tensile, and fatigue behavior of the copper matrix composites reinforced by steel particles are investigated. The composite grades containing 2.5, 5.2, and 7.4 wt% steel particles up to 90 µm in size are manufactured by the casting method. The microstructure of the composite samples is studied by scanning electron microscopy. The tensile and fatigue test samples are prepared and tested based on the ASTM standard. Adding 2.5 wt% steel particles to the copper matrix increases the yield strength, tensile strength, and elongation of the pure copper by about 48, 21, and 4.8%, respectively. The fatigue test results show that reinforcing the pure copper with 2.5 wt% steel particles improves the fatigue life of the pure copper by 67, 31, and 86 percent in 60, 80, and 100 MPa amplitude stresses, respectively. On the other hand, further increasing the reinforcement particle content to 5.2 and 7.4 wt% causes unusual fatigue behavior and adversely affects the mechanical strength of the composite. Therefore, the fatigue life of the composite samples reinforced by more than 5.2 wt% steel particles is not a function of the stress level and does not increase with the decrease of the stress. Manuscript profile