We present a study focussed at the atomic level characterization of the Fe/MgO(001) interface by means of X-ray photoelectron spectroscopy, X-ray photoelectron diffraction and X-ray absorption spectroscopy. The data show a good crystalline quality of the Fe films grown on MgO(001) at room temperature. The films have a bee structure with the Fe(001)//MgO(001) and Fe[110]//MgO[100] orientation. The Fe growth in the 1-10 ML thickness range proceeds by the formation of islands covering a fraction of the MgO surface. The oxidation of Fe and the consequent reduction of MgO can be excluded, thus proving that the interface is locally abrupt, with a very weak interaction between the two sides. The interface is stable with temperature up to 670 K.