A detailed study of EXAFS data has been used to evaluate the microstructural properties of grains forming the sample. A new model is proposed to determine the average dimensions of nanometric thin film iron grains, considering them as elongated particles, and taking into account polarization of the incident X-ray. Results show a clear decrease of grain size as the preparation temperature diminishes, and they are in very good agreement with previous measurements determined by X-ray diffraction techniques. (c) 2005 Elsevier B.V. All rights reserved.