We propose a general term flux-mediated epitaxy (FME) to single crystal quality of complex oxide thin films in vapor-phase epitaxy. The key is a flux, which is frequently used in a bulk process for lowering a process temperature and suppressing incongruent melt. The successful application of the flux to the bulk single crystal growth allows us to expect a similar benefit even in the case of vapor-phase epitaxy. In this paper, we discuss on the capability of this general concept 'FME' for controlling phases and crystallinity of the complex oxide films, showing some examples such as optical, ferromagnetic oxide and high-T-c superconductor. (c) 2004 Elsevier B.V. All rights reserved.