Interaction between regional trade agreements (RTAs) and the multilateral trading system established by the World Trade Organization (WTO) is an issue of significance but nevertheless remains unsettled. This article aims to explore the influence RTAs have generated had on the WTO system, with particular focus on the approach adopted by the adjudicators when dealing with irreconcilable RTA–WTO conflicts. During the development of 20 years’ jurisprudence, WTO adjudicators offered responses to a number of critical questions. On the one hand, direct endorsement of RTA provisions with the effect of prevailing over the counterpart WTO rules appears to be very difficult, either through legal interpretation or application. On the other hand, unlike often being argued, a close review of WTO case law does not reveal a biased adjudicatory approach against regionalism, as compared to other sources of public international law. When dealing with RTA-related matters, the Appellate Body has been advocating an all-encompassing approach featured by the emphasis on the common intention during the interpretative exercise and the promotion for the WTO built-in mechanisms for valid modification. Such an approach is, to a certain extent, misleading in the RTA –WTO context and has led to certain ill-founded adjudicatory choice.