The necessity of studies of the kinetics of beryllium (Be) oxidation by water vapor is motivated by the safety concerns at the emergency inflow of water into the plasma chamber of the ITER reactor. The chemical contact of water vapor with the Be-coated inner surface of the plasma chamber may lead to the production of hydrogen and vaporized toxic oxide of Be. The paper presents data on interaction between compact, porous and powder beryllium and water vapor in the temperature range of 400-1000degreesC at pressures 0.5, 1.3 and 3 atm as dependences of the reaction rate constant on temperature, pressure and beryllium oxidation degree.