Merger control constitutes an important part of competition law. Even though it emerged later than antimonopoly provisions it is now perceived as an indispensible tool for protection of effective competition. Merger control rules are under constant development so as to capture all new economic forms of concentration between undertakings and to remain an effective tool to prevent any anticompetitive concentrations and induce as few transaction costs as possible. Driven by this concept, the Polish Office of Competition and Consumer Protection (OCCP) decided to organize an international workshop devoted to new challenges in merger control across Europe. The workshop was held on 12 September 2013 in Warsaw. It consisted of two roundtables. The first roundtable discussed the topic of anticipated changes of EU Merger Regulation. The second one aimed at exchanging of experiences with designing and implementing remedies. The speakers came from different jurisdictions from competition authorities as well as from law firms.