Abstract Ultrasonic fatigue tests were carried out on the Inconel alloy 718 on pre-corroded and specimens without pre-corrosion. At high applied stress (up to 746 MPa) the specimens without pre-corrosion show fatigue endurance higher compared with the pre-corroded specimens with a factor of 10; whereas at low stress level (close to 510 MPa), the difference is considerably reduced; nevertheless, non-pre-corroded specimens show slightly higher fatigue endurance. Numerical investigations were carried out to obtain the stress concentration factors induced by the corrosion pits and the stress intensity factor in mode I was evaluated using the Stress Interpolation Method. Finally, the fracture surfaces were analyzed in order to identify the principal trends of crack initiation and propagation in this aeronautical alloy, under ultrasonic fatigue testing.