DLTS studies of electronic states and properties of the selfinterstitial in α-irradiated p-Si and n-Si are performed. The injection-enhanced annealing is observed for two traps E2 (Ec -0.39 eV) and El (Ec -0.26 eV) in p-Si. The annealing of E2 and E1 are simultaneous with the growth of hole traps connected with vacancy (V), Ci and Ali. It is concluded that the observed electronic levels belonq to different charge states of silicon selfinterstitial. The conclusion is confirmed by the differences of cross sections of the formation of Ali and Ci, by the influence of the zero and reverse bias conditions on the introduction rate and optical annealing of the E2 state in p-Si as well as by DLTS spectra of n-Si.