Specimens designed to reproduce the state of stress of the dovetail joint between blade and disk in a typical gas-turbine configuration have been tested in a 250-kN capacity biaxial fatigue machine. The materials tested were Ti-IMI 829 (disk and blade), Inco 901 and steel FV535 (blades only). The investigation highlights the importance of fretting at the disk/blade interface. A design parameter that combines fretting damage and peak stress is proposed as a basis for the life assessment of the joints.