The kinetic characteristics (the product partial pressures P and activation energies E-a) of the dehydration of Li2SO4 . H2O reported in a number of available publications have been analysed with the supposition of dissociative evaporation of the hydrate in the form of Li2SO4 and H2O molecules. Despite the considerable differences in the measurement conditions, the experimental values of P and E-a have been found to be in good agreement with theoretical calculations. The calculations took into account the depressing effect of water vapor on the dehydration rate and partial transfer of the energy released in the condensation of Li2SO4(g) to the reactant. The agreement between the calculated and experimental data supports the proposed mechanism of dehydration.