A coating with duplex structure of a outer beta-NiAl and an inner alpha-Cr layer, was formed on a Ni-40Cr-3Re (in at%) alloy with or without Zr addition, and the coated alloys were oxidized under thermal cycling in air for up to 2300ks. The coated alloys containing Zr showed a two-step parabolic oxidation, the kp(1st) in the early stage of oxidation was 2.6 similar to 5.4 x 10(-11) kg(2.)m(-4.)s(-1) for four alloys tested, and k for the longer oxidation increased with increasing Zr content from 2.6 similar to 5.4x10(-11) for the alloy with 0.1at%Zr to 9.6x10(-11) kg(2.)m(-4.)s(-1) for the alloy with 1.0at%Zr. The rapid oxidation for the alloy with 1.0at%Zr is due to the formation of ZrO(2) as an internal oxide. The oxide scale in the 1(st) stage consisted of both alpha- and theta- Al(2)O(3) with whiskers, and with further oxidation the alpha-Al(2)O(3) became the major product in the 2(nd) stage. After the oxidation for 2300ks the as-prepared, outer beta-NiAl was changed into a mixture of beta-NiAl and gamma'-Ni(3)Al for the Ni-40Cr-3Re alloy containing Zr, while in the coated Ni-40Cr-3Re alloy the outer layer became a mixture of gamma'-Ni(3)Al and gamma-Ni(Al,Cr). It was concluded that the addition of Zr into the coated Ni-40Cr-3Re alloy helps maintain high Al contents in the outer Ni-aluminide layer by forming a protective Al(2)O(3) layer.