The goal of this study is to understand how the microinclusions affect the fatigue life of rolling bodies. In order to do this, a numerical method was considered, and its results were correlated with experimental ones, investigating whether a microinclusion threshold parameter could be defined, to be related to the life bearing requirements. Many phenomena are involved in damage of rolling elements of bearings. Rolling contact fatigue is the main cause of failure, along with contact pressure related fatigue and dimensional instabilities effect. Most of those are well known, and are described by wide experimental, analytical and numerical literature. Damage phenomena are related to material properties and manufacturing processes.