The innovative potential of a non-commercial apparatus for simultaneous in situ Atomic Force Microscopy (AFM) and Energy Dispersive X-ray Reflectometry (EDXR) measurements is presented. A comparison between the two techniques, probing the samples surface in the direct and the reciprocal spaces, respectively, provides a deeper inspection in the surface morphology. Additionally, X-ray Reflectometry applied to films gives joint information on the surface and bulk morphology. The results on a gas sensing film demonstrate how simultaneous time-resolved AFM/EDXR allow the film surface/bulk morphology to be monitored, offering a unique tool to study the active materials in film-based technological devices in operating conditions. (C) 2009 Elsevier B. V. All rights reserved.