The oxidation behavior of four Ti-Al-Nb ternary alloys with different microstructures were investigated at 1000 C using interrupted oxidation test in air. Alloys with single-phase gamma-TiAl, two-phase gamma-TiAl + alpha(2)-Ti3Al, multi-phase gamma-TiAl + alpha(2)-Ti3Al + Nb2Al and two-phase alpha(2)-Ti3Al + Nb2Al were prepared. The oxidation resistance of the Ti-Al-Nb ternary alloy at high temperature was found to be better than that of the binary Ti-Al alloy. Among the four Ti-Al-Nb ternary alloys, the gamma + alpha(2) two-phase alloy has the best oxidation resistance. The presence of Nb-enriched phase such as Nb2Al and Nb3Al decrease the oxidation resistance at elevated temperature presumably due to the formation of Nb2O5, which would accelerate the exfoliation of oxide. (C) 2004 Kluwer Academic Publishers.