Aiming towards insight into the stability of newly developed advanced ceramic membrane materials, the time- dependent deformation at elevated temperatures is particularly important, where special consideration should be given to application-relevant atmospheres. This study examines the influence of Zr4+ doping on the creep behavior of BaFeO3-delta in air and nitrogen atmospheres at temperatures between 700 degrees C and 900 degrees C under compressive stresses ranging from 20 MPa to 60 MPa. BaFeO3-delta creep investigations revealed a transition from primarily diffusive to a combination of diffusive and dislocation-based mechanisms, owing to increasing oxygen deficiencies with increasing temperatures that culminate in a low to high symmetric crystal structure transition. Zr4+ doping improved the creep resistance and altered the creep mechanism to a predominantly dislocation- based mechanism, accompanied by a transition to a cubic crystal structure. Nitrogen atmospheres negatively affected the creep resistance of BaFeO3-delta and BaFe 0.9 Zr 0.1 O 3-delta , increasing the creep deformation rates for all temperature and stress levels.