A Mobile X-ray stress diffractometer has been designed13; and fabricated . This can be used to measure residual13; stresses in components quot;in situquot; nondestructively. To facilitate the alignment of the goniometer with respect to the job variuos movements, coarse and fine, are vailable . Stepper motors, controlled by the computer, drive the source and detector. The inclination angles can be selected from 0' to 45' in steps of 5'. The diffractometer can be operated either in the automode or semiautomode. in the auromode values of young's modulus and poisson's ratio are to be given and inclination angles selected. It searches for peak, determines peak position for all inclination angles selected, calculates stress and prints out results. Typical resultes are presented.