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Casting defects favor early fatigue crack initiation strongly dependent onthe initiating pore size and shape. This paper reports a study, in which specimensextracted from real castings and used for high-cycle rotating bending fatigue testingwere examined with metallographic techniques. The Murakami’s statistical methodbased on the largest extreme value distribution was used for the statistical descriptionof the pore size population observed on metallographic cross-sections. The largestdefect sizes occuring in real castings were predicted by this statistical method. Thefatigue fracture surfaces of the specimens were observed by scanning electronmicroscopy (SEM) and the fatigue crack initiation places identified. After the fatiguecrack initiation also the cracks propagation was examined and the crack paths weredetermined. Fracture mechanics based predictions were compared to experimentalresults.