Main goal of the present study was to shed light on fatigue performance and related mechanisms of 3D-printed superalloy compared to conventional cast one. Hence three thermodynamical states were considered: cast heat-treated, printed as-built and printed heat treated. Cylindrical specimens were machined out of blocks which were printed in horizontal and vertical building direction. Fatigue tests were performed at room and elevated (800 °C) temperature in low-cycle fatigue regime. Tests were controlled with total mechanical strain amplitude, strain rate was constant. Subsequently, specimens were analysed by means of scanning and transmission electron microscopy. The influence of the initial microstructure, heat treatment, building direction and temperature on fatigue behaviour has been discussed.