A theoretical investigation has been performed on the oxidative addition reaction pathway involved in the platinum-catalysed hydrosilylation of alkenes, analysing the oxidative addition of SiH4 to a platinum-diphosphine complex, Pt(PH3)(2). Static and dynamic density functional calculations have been performed in order to investigate the reaction mechanism and dynamics of the oxidative addition reaction in the considered system. Our results indicate that the oxidative addition is both thermodynamically and kinetically favored and takes place via a reactant-like transition state leading directly to the more thermodynamically stable cis-[PtH(PH3)(2)-SiH3] square-planar product. (C) 2002 Elsevier Science B.V. All rights reserved.