This paper presents the results of experimental investigations carried out on the synthesis of pure ZrB2 by boron carbide reduction of ZrO₂ and densification with the addition of HfB₂ and TiSi₂. Process parameters and charge composition were optimized to obtain pure ZrB₂ powder. Monolithic ZrB₂ was hot pressed to full density and characterized. Effects of HfB₂ and iSi₂ addition on densification and properties of ZrB₂ composites were studied. Four compositions namely monolithic ZrB₂, ZrB₂+10% TiSi₂, ZrB₂+10% TiSi₂+10% HfB₂ and ZrB₂+10% TiSi₂+20% HfB₂ were prepared by hot pressing. Near heoretical density (99.8%)was obtained in the case ofmonolithic ZrB₂ by hot pressing at 1850 °C and 35 MPa. Addition of 10 wt.% TiSi2 resulted in an equally high density of 98.9% at a lower temperature (1650 °C) and pressure (20 MPa). Similar densities were obtained for ZrB₂+HfB₂ mixtures also with TiSi₂ under similar conditions. The hardness of monolithic rB2wasmeasured as 23.95GPa which decreased to 19.45 GPa on addition of 10% TiSi₂. With the addition of 10% HfB₂ to this composition, the hardness increased to 23.08 GPa, close to that ofmonolithic ZrB₂. Increase of HfB₂ content to 20% did not change the hardness value. Fracture toughness ofmonolithic samplewasmeasured as 3.31 MPa m^1/2,which increased to 6.36 MPa m^1/2 on addition of 10% TiSi₂.With 10% HfB₂ addition the value of KIC wasmeasured as 6.44MPa m^1/2, which further improved to 6.59 MPa m^1/2 with higher addition of HfB₂ (20%). Fracture surface of the dense bodies was examined by scanning electron microscope. Intergranular fracture was found to be a predominant mode in all the samples. Crack propagation in composites has shown considerable deflection indicating high fracture toughness. An oxidation study of ZrB₂ composites was carried out at 900 °C in air for 64 h. Specificweight gain vs time plot was obtained and the oxidized surface was examined by XRD and SEM. ZrB₂ composites have shown a much better resistance to oxidation as compared to monolithic ZrB₂. A protective glassy layer was seen on the oxidized surfaces of the composites.