Purpose: In the paper the results of chemical composition investigations of passive layers formed on implants made of Cr-Ni-Mo steel, Co-Cr-W-Ni alloy and Ni-Ti alloy have been presented. Design/methodology/approach: Chemical composition investigations of the passive layer have been carried out with the use of X-ray Photoelectron Spectroscopy (XPS). The X-ray photoelectron spectroscopy with monochromatic radiation AlK α of 1486,6 eV was applied. The tests were carried out on the samples of polished as well as polished and passivated surfaces. The measurement of photoelectron spectrum in the wide range of binding energy from 0-1400 eV and precise measurements of the spectrum lines of elements from the surface layer were conducted. Findings: The chemical composition analysis of passive layers on the Cr-Ni-Mo steel, the Co-Cr-W-Ni alloy and the Ni-Ti alloy has revealed the presence of the following elements: (C, N, O, Na, Mg, Ca, Cr, Fe, Ni), (C, O, N, Cr, Fe, Co, Ni, W) and (C, N, O, Na, Si, S, Cl, K, Ca, Ti, Ni) respectively. Research limitations/implications: The research was carried out on samples, not on final parts. The tests were carried out in in vitro conditions. The obtained results are promising however further studies, in particular in blood environment, will determine a usefulness of the suggested technique of stents' surface improvement. Originality/value: The obtained results show the usefulness of the applied surface treatment to refine surfaces of implants made of the Cr-Ni-Mo steel, the Co-Cr-W-Ni alloy and the Ni-Ti alloy.