The wide use of ion implantation as a doping step in electronic device manufacturing stimulated a large number of scientific papers aimed at understanding the physical effects of the process on the target substrate. Among the different structural investigation methods, such as transmission electron microscopy techniques and Rutherford back-scattering/channelling of high energy light ions, X-ray diffraction in multicrystal optical geometries is preferable because of its high sensitivity to weak lattice strains. In Sect. 2 an X-ray diffraction formalism will be briefly outlined for multiple layers. This because simulation procedures of calculated kinematical (Speriosu, 1981), semikinematical (Kyutt et al., 1980) and dynamical (Wie et al., 1986) intensity profiles (rocking curves, RCs) to experimental data demonstrated that the depth-dependent structural damage distribution caused by ion bombardment is well described by step-like functions.In Sect. 3 the most suitable diffraction optics, either dispersive or non-dispersive, to make measurements in the highest resolution mode will be described and the calculation procedures to best fit the experimental RCs will be the subject of Sect. 4. Finally, examples of application will be reported in Sect. 5 to show how information on the features of the implant process can be extracted from RC analysis. In particular, attention will be drawn to (i) the formation of lattice defects and their evolution after thermal treatments,(ii) the effects of the nuclear and electronic energy losses of the