This chapter discusses atomic defects in iron (Fe). The defect research on α-Fe has met characteristic difficulties, related to the structural and magnetic phase transitions. Also trace impurities of carbon play an important role. The preparation of high-purity iron requires the combination of different techniques. Residual traces of carbon can have an important influence on the obtained numerical values, also the correction for the ferromagnetic state. Resistivity recovery data following electron irradiation show a recovery spectrum very similar to fcc metals. This is in contrast to other bcc metals (Mo,W), where IE is strongly modified. Survey on the resistivity recovery stages in iron as observed after e--irradiation, peak temperature of the differential isochronal recovery curve and reaction order of a recovery process in terms of a rate equation are tabulated. Properties of Frenkel defects, self-interstitial atoms (SIA) and vacancies (V) in iron are discussed. V-solute atom (SA) interactions and SIA-SA interactions (dissociation temperature) is provided. Resistivity recovery of electron irradiated iron at various temperatures, resistivity recovery of electron irradiated iron, influence of carbon doping, resistivity recovery of various cold-worked iron probes and resistivity recovery of high purity iron after fission- and fusion-neutron irradiation are shown in the figures.