Thin films of diamond-like (DLC) and graphitic materials are characterized by low thermal expansion coefficients, high thermal and electrical conductivities and chemical inertness. DLC, in addition, exhibits extreme hardness. The problem of DLC thin films characterization by electron spectroscopy is presented. The outstanding problem is the determination of the ratio of carbon atoms with diamond-like sp 3 tetrahedral bonding to carbon atoms with carbon graphitic sp 2 trigonal boding. This ratio results from the quantitative percentage composition of the DLC thin films. We report the characterisation by XPS and XAES of the diamond vs. graphite nature of several amorphous carbon thin films deposited by Laser Ablation of PMMA (poly methyl methacrylate).