Spintronics has been greatly benefiting from the investigation of the ferromagnet-semiconductor interface. In this work, a study of the reconstructions of Si(001) and InP(001) surfaces, and the characterization of thin Fe films grown on these substrates are presented. To suppress Fe-Si reactions, a Au buffer layer was grown in two steps on (2 × 1) Si(001). First, a reconstruction of the Si(001) surface was performed by the deposition of less than one monolayer of Au at around 1000 K. Second, an ultrathin Au layer was added. It was found that the role Au plays is twofold: it hampers Si out-diffusion, and establishes the perpendicular magnetization in the Fe film. Accordingly, it was inferred that no magnetically dead layers form at the interface. The InP(001) substrates cleaned by ion bombardment showed a P-rich (2 × 4) reconstructed surface. Auger electron spectroscopy data revealed that Fe-InP intermixing is negligible. The current-voltage characterization of patterned Fe films grown on n-InP(001) showed non-rectifying contacts at room temperature. A uniaxial in-plane magnetic anisotropy was observed in ultra-thin films and the surface/interface contribution was assessed. From the magnetization behavior it was deduced that very small, if any, magnetically dead layers form at the interface. The presented results make the Fe-Si and Fe-InP systems good candidates for spintronic applications.