Hydrogen ion cleaning procedures of InP(100) surfaces have been studied and the effect of hydrogen on carbon and oxygen contaminations were particularly investigated. The induced structural surface modifications were studied by x‐ray photoelectron spectroscopy andinsitureflected high‐energy electron diffraction just after ion bombardment and after annealing under an arsenic overpressure. Results show that cleaning with hydrogen ions leaves an indium‐rich surface layer on the InP surface. After hydrogen ion bombardment, structural changes of the surface occur and their irreversibility after As stabilization depends on the hydrogen dose. If this dose does not exceed a critical value of about 3×1016ions/cm−2, the structural properties of the InP surface can be restored after thermal annealing under arsenic overpressure. However, both unannealed and annealed surfaces show a strong pinning of the Fermi level, with the creation of defects 0.25 eV below the minimum conduction band, which indicates poor electronic properties always after hydrogen ion bombardment.