Mono-nuclear amide complexes, their substituted complexes and bi-nuclear amide complexes of ruthenium, reported earlier by us, have been used as catalysts for the epoxidation of olefins. The complexes exhibit low to moderate catalytic activity. The electronic spectra and electrochemical study of the catalyst does not show any change on the addition of PhIO, ruling out the involvement of the metal-oxo intermediate and hence the oxygen rebound mechanism. The catalytic reaction has been explained on the basis of lewis acid behaviour of the ruthenium centre in these complexes. (C) 2002 Elsevier Science B.V. All rights reserved.