The characteristics of defects induced by Si and Ga focused ion beam (FIB) implantation inn‐GaAs have been investigated by means of deep‐level transient spectroscopy (DLTS),C–Vcarrier profiling, and resistance measurements. The DLTS spectra of Si and Ga FIB implanted samples annealed at temperatures up to 500 °C are apparently identical to one another and show three different electron traps with an activation energy between 0.25 and 0.6 eV. The resistance increases by more than five orders of magnitude by Si and Ga FIB implantation due to the induced defects. However, it is restored to initial values after annealing at 600 °C, except for a sample of Ga implantation with a dose higher than 1014/cm2. For annealing of induced defects, there are no intrinsic problems for FIB implantation with a dose lower than 1013/cm2.