If the intensity of microwave radiation of less than 10 mW·cm^–2 the increase in radio-resistance is realized. In the case where the intensity of the microwaves is greater than 10 mW·cm^–2, radio-resistance is reduced. It is shown that low intensity microwave provides an increase in the permeability of cell membranes, but the temperature of the cell, has not changed. This increases the enzymatic activity, thereby increasing to radio-resistance of biological object. Powerful microwaves, on the contrary, much heated to the biological cells, contributing to their destructions. The presence of disruptive disorders in a cell lowers resistance bioobject to the ionization radiation.