The objective of the presented work was to compare the properties of the two surface modifications of Ti-6Al-4V alloy. In the first case, a nanostructure of a tube character was constructed electrochemically under defined conditions and in the second case the alloy was coated with a DLC layer. Surfaces were analyzed in terms of their composition and morphology. Electrochemical impedance spectroscopy study of the specimens' interaction with a simulated body fluid followed. The interaction of the modified surfaces with the cell environment was evaluated using heteronuclear cell line MG 63. Both surface treatments lead to improve of biological properties of studied alloy. (c) 2012 Elsevier B.V. All rights reserved.