We investigated how tensile dwells in thermo-mechanical fatigue (TMF) tests affect the deformation, damage and lifetime behaviour of Inconel 718 manufactured by electron beam melting. The TMF tests were conducted in laboratory air under in-phase conditions with a temperature range of 300 to 650 °C. Optional tensile dwell times were introduced at the maximum temperature. The findings are discussed based on microstructure and damage observations using SEM and light microscopy.