Transmission electron microscopy and electron backscatter diffraction in the scanning electron microscope have been used to investigate particulate composites with the tetragonal zirconia polycrystalline (TZP) matrix. Two carbides, mainly TaC and NbC, chemically stable in relation to zirconia, have been selected as reinforcing inclusions. Their incorporation into the TZP matrix resulted in significantly better mechanical properties of the investigated systems. The way of explaining such a phenomenon is to analyze the crystallographic correlations between the oxide and carbide phases which may influence the strength of the interphase boundary and finally lead to an increase of fracture toughness and wear resistance of the composite. (C) 2003 Elsevier Science B.V. All rights reserved.