Thin films of La0.7Sr0.3MnO3 and La0.7Sr0.3FeO3 have been deposited on single crystal yttria-stabilized zirconia (YSZ) substrates using molecular beam epitaxy. Due to the large lattice mismatch, three-dimensional growth is observed with strain relaxation occurring within 1-2 unit cells. The as-grown perovskite/YSZ interfaces are abrupt, despite the imperfections associated with strain relaxation. The films exhibit a single crystallographic orientation along the growth direction, with the perovskite [011] parallel to the YSZ [001]. Synchrotron diffraction and plan view transmission electron microscopy reveal the presence of a columnar grain structure with the in-plane [100] and [01 (1) over bar] film directions preferentially orientated along the YSZ < 100 >. The stabilization of perovskites on YSZ substrates with abrupt interfaces and a well-defined crystallographic orientation allows for the use of thin film model systems to study cathode/electrolyte interfacial reactions and morphological changes relevant to solid oxide fuel cells. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.032208jes]