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Fatigue design of notched parts is customarily performed using theconcepts of elastic stress concentration and material notch sensitivity. However, if thismethodology is applied to gray cast irons the predictions appear far from satisfactory.Due to its microstructure, gray cast iron exhibits a marked brittle behavior and a lownotch sensitivity. Various authors have proposed alternative approaches: among themfracture mechanics based approaches and critical distance methods. This paperexamines fatigue crack initiation at sharp notches in gray cast iron from both theexperimental and the theoretical point of view. Fatigue life and fatigue crack initiationexperiments are conducted on V-notches specimens extracted from castings in fullypearlitic gray iron. Different values of notch root radii are examined. From atheoretical point of view, the notch root stresses in the test specimen geometries areinvestigated with the FE method. The role of the notch elastic stress concentration onthe microstructure is discussed and the possibility to identify microstructure-dependentvalue of a critical distance or intrinsic fatigue crack length at a V notch is investigated.