The epitaxial growth of Fe monolayers on the unreconstructed Ir(001) surface was investigated experimentally by determining film structure, morphology, stress, and magnetism. Our combined quantitative low energy electron diffraction (LEED) and cantilever stress results indicate pseudomorphic Fe growth with a constant in-plane film strain in an almost perfect layer-by-layer growth mode from 0–10 layers. The combination of the structural analysis by LEED with stress measurements suggests that the first two layers of Fe grow as a face-centered tetragonally (fct) distorted precursor. Further deposition of Fe leads to the growth of a body-centered tetragonally distorted phase on top of the fct precursor, which retains its structure. The magneto-optical Kerr effect reveals that the Fe film is ferromagnetic with an in-plane easy magnetization direction along Fe<100>.