Hydrogenated amorphous carbon (a-C:H) films were deposited by the r.f. plasma technique in order to study the effect of deposition parameters on the mechanical and tribological properties of the films. An experimental design method was used for planning the experiments, and statistical analysis and modelling to analyse the results. The high hardness of the film was found to have the highest correlation with the good wear resistance of the film. By using response surface modelling, some direct trends from the process parameters to tribological properties were found. The best wear resistance for the a-C:H films was found for low pressure (0.7-2.5 Pa) and intermediate bias voltage (-550 V) values. By using the experimental design, the number of deposition runs could be reduced, and the statistical analysis and modelling provided useful and precise information showing also the significance of the trends observed.