The cyclical oxidation behavior of the electroless Ni-P coating and of the Ni-P-pure magnetite and Ni-P-Aldoped magnetite composite coatings on stainless steel has been studied. During the tests, the bare steel lost mass catastrophically, whilst the samples of coated steel lost mass in a very small amount, showing oxide growth curves that agreed with successive parabolic laws. X-ray diffraction studies of the oxides confirmed that the phases with major concentration were α-Fe2O3 on bare steel, NiO on ENP and NiMnxCr2-xO4 (with x=0.2 and 1) on composite coatings. The scanning electron microscopy and energy dispersive spectroscopy analyses showed that both, the oxide scale and the coatings evaluated hindered the inward diffusion of oxygen towards the steel substrate.