This paper presents a methodology for analyzing the multiaxial loads acting on a steering knuckle under operating conditions. The knuckle is a critical structural part which connects the wheel in a car to the steering and suspension system. Computeraided modeling and analysis were carried out on the knuckle, and the results were compared for conventional and metal matrix composites (MMC) with ANSYS software. The simulation showed that the steering-arm region failed under cyclic load conditions. Accordingly, the knuckle was optimized with a genetic algorithm and a modified design was proposed. Steering knuckles were fabricated from three different materials: ductile iron, LM 6 alloy and MMC with a modified design were experimentally tested in the steering-arm region to evaluate the fatigue life. Simulation results showed that the fatigue life of the MMC knuckle was 1.946E+06 fatigue cycles after optimization whereas experimental results showed 1.20E+06 cycles. Knuckle weight reduction of 60% was achieved by replacing ductile iron with MMC. Hence it is recommended to use MMC steering knuckles in automobiles.