To study the structures of amorphous Si (a-Si) and amorphous hydrogenated Si (a-Si:H), we have measured Si L-2,L-3-edge ELNES spectra of these systems and crystalline silicon (c-Si) for the reference by use of the transmission mode. The observed spectra are carefully studied by use of the full multiple scattering calculations. The observed differences of the spectra for a-Si and a-Si:H from that for c-Si are well explained by some plausible models. The analyses of the ELNES for a-Si support the defect model where some Si atoms are removed away, and those for a-Si:H support a hydrogen substitution model where some Si atoms are randomly substituted by H atoms keeping the diamond structure (C) 2003 Elsevier Science B.V. All rights reserved.