The method of Bollmann has been used to determine the role of epitaxy in the formation of the mechanical stress field near the metal/oxide interface during the high temperature oxidation of zirconium, The strains due to epitaxy combine with those due to both oxygen diffusion in metal and thermal expansion of the metal/oxide composite in a model based on a micromechanical formalism. The calculated values are compared to experimental results and the applicability of Bollmann's method to this problem is discussed.