Physico-chemical and catalytic properties of silver catalysts modified by Zr, Ce, La, Rb and Cs oxides have been studied in the process of the selective oxidation of methanol. Modifying additions in amounts of 1-10 wt.% change the effective charge and redox properties of supported silver, the metal dispersivity and its surface diffusion, surface acidity of the catalyst and degree of coking in the process of oxidation of methanol to formaldehyde. The influence of the modifier on the electronic state of the catalyst active sites (Ag+, Agϑ+n) is of primary importance when varying the catalytic properties of silver.