Being focused on the effect of TiC content, the oxidation behavior of the sintered WC-TiC-TaC alloys with 2 mass% TaC and different TiC amount of 3-45 mass% was investigated. It was revealed that mass changes from oxidation and thickness of the oxidation scale decreased with increasing TiC content in the alloys. The main component of the scales changed from WO3 to TiO2 gradually with increasing TiC content in the alloys, and hence oxygen diffusion through the scale to the alloys was inhibited more and more.