During investigations into the activity of the 8% WO3/SiO2 catalyst it was observed that the selectivity and online lifetime of the catalyst improved, while the overall feed conversion decreased slightly after the first regeneration. It was further observed that the online lifetime of the catalyst was different after the first regeneration of the catalyst. Analysis of the fresh, coked and regenerated catalyst did not show any sintering of the catalyst taking place. It was concluded that coking of the catalyst is mostly occurring, in the pores of the support. Analysis also indicated a possible change in the morphology of the catalyst after the first regeneration. The purpose of this investigation is to highlight the significant effect that regeneration has on the lifetime and selectivity of a WO3/SiO2 metathesis catalyst. (C) 2003 Elsevier B.V. All rights reserved.