This paper presents an overview of fatigue fracture modes in selected structural alloys employed in gas turbine engines. These include the mechanisms of fatigue crack growth in the near-threshold, Paris and high-DeltaK regimes obtained from Ti-6Al-4V, Inconel 718 and PWA 1472 (a single crystal nickel-based superalloy of similar chemical composition to Inconel 718). Fatigue fracture modes in these materials are shown to be strong functions of the stress intensity factor range, DeltaK, and the maximum stress intensity factor, K-max. Fatigue mechanism maps are also presented to show the parametric ranges of DeltaK and K-max corresponding to the different fatigue fracture modes. (C) 2003 Kluwer Academic Publishers.