Wood deterioration over time (by a simultaneously biological, chemical or physical attack) is an inevitable continuous process in the environment. This process destroys all heritage resulting in a loss of valuable old wooden structures and their properties. What type of deterioration occurs and how these processes impact the wood are important questions that need consideration if old wooden structures are to be studied and properly preserved. X-ray photoelectron spectroscopy (XPS) was employed to analyze the undegraded (sound wood of similar to 6 years) and degraded lime wood (similar to 150 years, similar to 180 years, similar to 250 years) from painting supports, differing in terms of the provenance, conservation status and environmental conditions of storage. Elaborated XPS analysis (comparison of C and O individual spectra, decomposition for each atomic component, calculation of O/C ratio) provided a view of the composition of the sample surfaces analyzed. On the basis of these results, it was confirmed that significant changes occurred in the first period of ageing, the similar to 150 years lime wood sample having the highest percent of the carbon atoms and the lowest percentage of oxygen atoms and, respectively O/C ratio. According to our previous studies (X-ray diffraction, FTIR spectroscopy, analytical pyrolysis combined with gas chromatography/mass spectrometry and ESR-spectroscopy results), these features could be attributed to the fact that hemicelluloses and amorphous cellulose are degraded in time, whereas the crystalline fraction of cellulose decreases more slowly than the amorphous one. Consequently, the observation may be made that lignin is not so easily degraded under the environmental conditions where paintings are frequently exposed. (C) 2009 Elsevier B. V. All rights reserved.