Material characteristics determined for low cycle fatigue (LCF), high cycle fatigue (HCF) or fatigue crack growth (FCG) are different. The question arises, whether common mechanical and microstructural features can be found or not in this field of loading types, based on which relationship among the materials constants can be assumed. The paper introduces the similarity of the stress and strain state, furthermore the dislocation structure having been developed during low cycle fatigue and fatigue crack growth. This can form a basis for the establishment of a connection between the material characteristics, the exponents of the Manson-Coffin equation and the Paris-Erdogan law. The validity of the hypothesis has been illustrated here by comparing the test results determined for different material grades, steels, one superalloy and aluminium alloys.