The repeated start-ups and shut-downs experienced by gas turbines cause complex thermal-mechanical loading, which may result in the low-cycle fatigue failure of components such as the walls of the combustion chambers. In addition, a higher frequency high cycle fatigue loading (HCF) is often superimposed due to mechanical vibrations and unsteady combustion processes. It is known that such a superimposed HCF loading may not only change the cyclic deformation behavior, but also reduce the lifetime considerably. In the present study, the cyclic response of a combustion chamber material, NiCr22Co12Mo9 (Inconel 617), was investigated under combined TMF/HCF loading in total strain controlled out-of-phase (OP) and in-phase (IP) TMF tests with and without superimposed HCF loading. The minimum temperature of the TMF tests was 200 °C, and the maximum temperature was varied from 750 to 1200 °C. For each maximum temperature condition, the superimposed HCF amplitude was varied between 0 and 0.2%. Cyclic hardening was observed, but it became less pronounced the higher the maximum temperature, and at the highest T_max the material was cyclically neutral. With increasing superimposed HCF amplitude the cyclic deformation behavior was more and more determined by the HCF. Further, as a result of the superimposed HCF loading the TMF lifetimes decreased significantly. In general, the lifetimes decreased with increase in HCF amplitude and approached only 10% of the fatigue lifetime obtained in the pure TMF experiments. The relation between the applied total strain amplitude, ε_a,t^me,and the number of cycles to failure, N_f, could be expressed as ε_a,t^me = A ∙ N_f^-b for each T_max and type of TMF-test. With the use of this empirically determined relationship it was possible to estimate the lifetime reduction caused by a superposition of a higher frequency HCF loading on the OP- as well as IP-TMF loading.