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Vickers hardness determination is a standard test procedure widely used in mechanical characterization of ceramic materials. Due to possible fragmentation, however, it is sometimes to detect and measure the indent diagonals for some polycrystalline ceramic materials. Moreover, hardness value often shows high variation with respect to the indentation load, causing some uncertainty in the definition of hardness as a material property. For this reasons, it has been attempted to obtain hardness value directly from the analysis of load–displacement curves (P–h) recorded by means of a suitable depth–sensing indentation test machine. In the present work depth–sensing indentation tests on pure alumina and a silicon nitride composite reinforced with whiskers of silicon carbide were performed. Two methods for the numerical interpretation of the P–h curves and developed for the direct determination of material hardness are proposed.