The albumin adsorption on non-hydrogenated amorphous carbon films with different diamond-like character (i.e. sp(3) content) is addressed. The films were produced by ion beam assisted deposition and by filtered cathodic vacuum arc deposition to obtain a wide range of sp(3) contents. A combination of the spectroscopic ellipsometry, Raman spectroscopy and elastic recoil detection analysis was used for characterization of the films. It is shown that an increase of the deposition temperature leads to a decrease of the film band gap, density and a shift of the Raman G-band position. The wettability of the film is not influenced by its sp(3) content. Albumin adsorption on the surface depends more on its wetting behavior than on the sp(3) content. In addition, Ar ion treatment of the layers can be used to reduce the amount of adsorbed proteins. (C) 2003 Elsevier B.V. All rights reserved.