This paper describes the influence of polydopamine surface modifications on the adhesion strength of electroless deposited copper on roughened epoxy resin substrates. The surfaces are characterized with XPS and ToF-S-SIMS. Next, a thorough investigation of the copper-epoxy interface is performed using SEM. Both the polydopamine modification and the variation of the electroless plating bath temperature lead to new insights into the different contributions of chemical and physical adhesion to the overall adhesion strength. (C) Koninklijke Brill NV, Leiden, 2012