The response of the structural parameters to applied stress was investigated in a conic single-crystal specimen of nickel-base superalloy CMSX-4 crept at 1100 C for 300 hours. The investigation was performed by Fourier analysis of scanning electron microscope images and by Xray diffraction. Measurement of the period of the gamma/gamma'-microstructure (total thickness of the gamma- and gamma'-rafts) and the gamma/gamma'-misfit along the specimen axis showed clear correlations of these parameters with the change of applied stress along the specimen axis. At stress levels greater than or equal to 40 MPa the measured change of misfit was described by a model proposed by the authors earlier. It is intended to continue the investigation to develop a method for the estimation of stresses acting in turbine blades during operation at high temperatures.