In this study, the effect of the Mg amount on microstructure and wear behaviors of A356 cast aluminum alloys is investigated. Al-Si-Mg alloys containing different amounts of Mg were produced by casting. The alloys were then aged at 170 degrees C for 10 h (T6). After T6 heat treatment, the samples were prepared for microstructure examinations and wear testing. Wear tests were performed with a pin-on-disc type wear testing device. Results of the study show that the hardness increases and the density decreases as the Mg fraction increases in the alloy. As a result of the wear test, the A356-0.43Mg alloy was found to have the highest weight loss and wear rate, whereas the A356-0.86Mg alloy has the lowest weight loss and wear rate. (C) 2018 Karabuk University. Publishing services by Elsevier B.V.