The oxide scales formed on $Ni_3Al$-7.8%Cr-1.3%Zr-0.8%Mo-0.025%B after oxidation at 900, 1000 and 110$0^{circ}C$ in air were studied using XRD, SEM, EPMA and TEM. The oxide scales consisted primarily of $NiO,; NiAl_2O_4,;{alpha}-Al_2O_3,; monoclinic-ZrO_2,; and ;tetragonal-ZrO_2$. The outer layer of the oxide scale was rich in Ni-oxides, whereas the internal oxide stringers were rich in Al-oxides and $ZrO_2$. Within the above oxide scales, Cr and Mo tended to exist as dissolved ions.