The interaction between hydrogen and irradiated defects in iron was studied. Different kinds of complexes of hydrogen and defects would form if hydrogen was trapped by the defects. During aging at various temperatures, it was observed that interstitial-type loops formed above 300℃, vacancy-type loops formed above 450℃ and voids formed at 520℃. We consider that such complexes as H-I or H-Is, H-V and H-Vs result in interstitial-type loop, vacancy-type loop and void, respectively.