The thesis analyses the conditioning factors of Canada’s and Japan’s bargaining power in the multilateral trade negotiations of the Uruguay Round and Doha Development Agenda (DDA). It deals with two related research questions. The central question of this research is: to what extent and why did Canada’s and Japan’s bargaining power decrease from the Uruguay Round to the DDA? This question is related to the following auxiliary research question: what are the conditioning factors of Canada’s and Japan’s bargaining power during the Uruguay Round and DDA, and to what extent have these factors changed from one round to the other? While the thesis includes a general overview of their negotiation profiles, it analyzes specific, detailed case studies of the profiles of these countries in anti-dumping and market access/NAMA negotiations in both rounds. The hypothesis of this research is that Japan and Canada have lost bargaining power from the Uruguay Round to the DDA because of changes in the following conditioning factors: economic power; activity in country coalitions and groups; interests groups and decision-making structures on the domestic level; ideational power; and foreign policy objectives. In addition, the importance of the position of the preferences a country in the spectrum of the overall membership of multilateral trade negotiations is examined. The thesis finds that this hypothesis is partially confirmed. Canada and Japan have mainly lost bargaining power owing to a relative decrease in their economic power, a lower profile in central negotiation groups as well as coalitions, and due to domestic politics. Ideational power and especially foreign policy objectives can be considered less relevant. The thesis also finds that especially Japan’s bargaining power in anti-dumping negotiations was affected by a change of the position of its preferences within the spectrum of the overall membership of the negotiations.