European Patents are granted through the European Patent Office. Although such right is unitary, the European patents will break down into a bundle of national patents; each governed by the domestic law of the States which the holder of the right has designated. Since infringement stands in the crossroads between patent enforcement and patent validity, infringement litigation generally touches on the issue of validity as it is impossible to infringe a right that does not exist or no longer exists. The nullity component in infringement litigation gives rise to additional difficulties with respect to the selection of the forum and the applicable law. As a result, the validity challenge is discussed in detail with respect to the application of the relevant rules on international jurisdiction and with respect to the identification of the relevant applicable laws. Cross border litigation in relation to registered intellectual property rights in Europe has been extremely controversial over the years. The jurisdiction of the courts to deal with foreign intellectual property rights is after all not entirely obvious or straightforward in the light of the exclusive jurisdiction provision in the Brussels system. The judgment which the Court of Justice delivered on 13th July 2006 in case Roche and GAT result substantial conflicts. Divergent views had been expressed concerning cross border jurisdiction over intellectual property cases on Article 6(1) of the Brussels I Regulation; and Article 16(4) of the Brussels Convention 1968, what is now Article 22(4) of the Brussels I Regulation. This thesis focuses on the jurisdiction and applicable law on European patent disputes.