The physico-chemical, adsorptive and catalytic properties of zeolites are mainly determined by the interstitial cations and their distribution over different sites in the cavities and channels of the zeolite lattice. Therefore, the knowledge of the cation distribution and of influencing parameters is of great theoretical and practical interest. On the basis of an analysis of structural data roles of cation distributions in A-, X- and Y-zeolites are postulated.