Abstract: We briefly review the Epstein-Glaser construction of time-ordered products in a modernized version due to Stora, Brunetti and Fredenhagen. We then show that the Hopf algebra of rooted trees, introduced in momentum space renormalization by Connes and Kreimer, encodes the combinatorics of Epstein-Glaser renormalization as well. In particular, we prove that the twisted antipode provides a complete set of counterterms. Finally we comment on relations to the Fulton-MacPherson compactification of configuration spaces.