Ethanol adsorption on Si(111)-(7 x 7) has been investigated by high-resolution photoemission in the valence band and the Si 2p and C Is energy regions. The valence band spectra show that, similarly to methanol adsorption on Si(111)-(7 x 7), ethanol adsorption is dissociative and occurs through O-H bond breakage and Si-O bond formation. However, at variance with a previous study, we find that the adsorption does not proceed selectively on surface rest atoms. The lack of site selectivity is also confirmed by the photoemission spectra of the Si 2p core level line. The possibility of a further fragmentation of the ethoxy species into a methoxy plus a methyl group is discussed. (C) 1998 Elsevier Science B.V. All rights reserved.