Most of the research reported in the literature on cast aluminum alloys is related to constant amplitude loading, while in most applications such components are subjected to variable amplitude loading conditions. In this work, fatigue performance of high pressure die cast (HPDC) A356-T6 aluminum alloy is evaluated using a real industrial load spectrum. Mean stress effect was also studied by conducting variable amplitude fatigue tests under two different mean stress conditions. Fatigue life estimations were performed following S-N approach as well as fracture mechanics approach using direct summation method as well as FASTRAN program assuming the defects as initial cracks. The size of fatal defects measured from fracture surfaces as well as the maximum defect size estimated by extreme value statistics were used in fatigue life estimations. The results of life estimations are compared and discussed with reference to the experimental results.