A new version of the concentration wave method is helpful is estimating the mechanism of hydrogen transfer through a NiO film. A mathematical model which adequately describes the process is offered. Arguments are advanced in favour of association-dissociation processes on inner NiO-Ni surfaces rather than on free NiO surfaces and in support of hydrogen movement as molecules along the oxide with a high porosity. The hydrogen diffusion coefficients between 643-783 K are determined in Ni and NiO (D₁ and D₂, respectively) and given by equations D₁=4×10^-3 exp (-4200÷T) and D₂=200 exp (-17000÷T) cm²÷s. The D₁ values are shown to be in close agreement with the data of measurements on nonoxidized Ni.