The paper deals with the possibility to control aging of MgH2 by controlling the deposited energy, number and type of defects and their distribution in the near surface region using Ar8+, Xe8+, and B3+ ion irradiation. The evolution of the obtained phases was monitored using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, laser scattering particle size distribution measurements and surface area analyses. Obtained results give the possibility to resolve between the material related (impurities, defects, strains) and the ambient induced component of aging. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.2308