The pack boriding process has been used to treat gamma-TiAl intermetallic compound at a boriding temperature of 940 degrees C for a boriding time of 8 h. A dense and continuous borided layer ca. 15 mu m thick was obtained on gamma-TiAl. The X-ray diffraction pattern depicts a single borate phase 9(Al,Ti)(2)O-3 B2O3 formed in the borided layer. Cyclic oxidation behavior of the borate coating has been investigated at an oxidation temperature of 800 degrees C with a total exposure time up to 100 h in air. The mass gain of the borate coating was 1.6 mg cm(-2), which is about three times lower than that of unborided gamma-TiAl. The 9(Al,Ti)(2)O-3 B2O3 phase decomposes slowly during the oxidation process at 800 degrees C in air. The stable borate coating improves the high temperature oxidation resistance of gamma-TiAl.