The influence of impurity gases on c-axis orientation for Co–Cr sputtered films was investigated, using x-ray diffraction analysis. The O2 partial pressure at which c-axis orientation begins to decline depends on the Cr content of films. C-axis orientation for higher Cr content films was not disturbed up to higher O2 partial pressure. Cr plays an important role in protecting films from oxidation during deposition. For c-axis orientation, N2 had equal influence on different Cr content films, and was more detrimental than O2. Reduction in c-axis orientation corresponded well to an increase in spacing of c planes with impurity gas addition and was, therefore, attributed to the entrapment of impurity gas into the film. This hypothesis was confirmed in the case of oxygen with Auger microscopy. O2 addition was considered to be advantageous because it suppresses grain growth without damaging c-axis orientation. Increase in saturation magnetization was observed only for higher Cr content films with O2 addition; although actual composition of the films was almost equal to that of the targets. Perpendicular coercivity and anisotropy fields of higher Cr content films decreased, even without reduction in c-axis orientation, with increased O2 addition.