In order to improve the oxidation resistance of C/C composites, an inhibitor mixing method was examined in this study. Combinations of oxidation inhibitors, B₄C, SiC, and ZrB₂ at various mixing ratios were tested in the temperature range from 800 to 1, 700°C. In an optimum mixing ratio, the inhibitor-mixed carbon showed superior oxidation resistance up to 1, 700°C. To understand under-lying mechanisms to yield such superior behavior, oxidation behavior of the inhibitor-mixed carbon materials were examined by measuring mass loss rates at various temperatures. In addition, the cross-sections of the as-fabricated and oxidized materials were observed with various microscopes. Based on these experimental results, it was concluded that the chemical interactions among the three inhibitors played important roles to yield the superior high temperature oxidation-resistance.