Stage I recovery of 1.5 MeV electron-irradiated BCC iron has been studied by electrical resistivity measurement.In situannealing of irradiated samples from 40°K to 140°K showed a complex substructure for Stage I recovery in both well annealed and partially recrystallized samples. Activation energies were obtained by Meechan-Brinkman combined isothermal-isochronal anneal method. Activation energies of 0.05, 0.10, 0.19, and 0.23 eV were determined for Substages IA, IB, ICand ID, respectively. The isothermal recovery of Substages IB, IC, and IDis best described by first order kinetics. A trapping interaction between the freely migrating interstitial atom and lattice defects is apparent in Substage IE. Results of this work are compared with other data for electron-irradiated iron and to various recovery models proposed.