We measured internal residual strain of GlidCopTM, a copper dispersion strengthened with aluminum oxide. The residual strains were measured by X-ray diffraction using synchrotron radiation. The purpose of this study is to verify the accuracy of an elastic-plastic analysis, which has been employed for the fatigue life prediction of GlidCop. As a result, the residual strain was estimated to be 0.11- 0.13% at any number of cycles, which is in good agreement with the analysis solutions. As to the plastic strain, we need to increase the accuracy of the calibration curve for the relationship between the FWHM of the diffraction profile and the plastic strain.