Deep levels in iron‐diffused heavily boron‐doped silicon are investigated by means of deep‐level transient spectroscopy (DLTS). For interstitial iron Feia donor state is observed at 0.39 eV above the top of the valence bandEv. It is proposed that Feiexhibits charge‐dependent annealing characteristics, and in its neutral charge state Feiis mobile at temperatures as low as ≊280–230 K. Three other Fe‐related donor states are observed atEv+0.53 eV,Ev+0.60 eV, and ≊Ev+0.63 eV. The latter two states, not reported in any previous DLTS study, are produced in comparable concentrations to that of Feiupon annealing at 100 °C, whereas the former state present directly after quenching is suggested to result from a complex defect containing Fei. It is also argued that the level observed in this study atEv+0.60 eV is the same as the one reported earlier at 0.55 eV below the bottom of the conduction band, but that it corresponds to a donor state of an Fe‐related defect, in contrast to previous suggestions of it being an acceptor state. The annealing behavior of the defect states observed is studied up to 300 °C, and possible interactions involving Feiare discussed.