The international trade regime embodied in the World Trade Organization (WTO) goes beyond a collection of texts and agreements. As legal rules are not immune to political and economical influences, they have to be analysed in the context in which they have been created and constantly modified. Nowadays, the multilateral system of the WTO gains complexity when the market place does not restrict its subject to goods anymore and when the goal of development is materialized, in its agreements, as one of the pillars of the WTO. Developing countries, empowered by the launch of their economic growth, are acquiring space and voice to criticize the legal framework of the WTO, saying it has not been entirely coherent with its own objectives and claiming for the adoption of an effective Special and Differential Treatment (SDT). On the other hand, developed countries, based on their economic superiority and underlining the importance of free trade through liberalization policies, insist on the necessity of reciprocal commitments to promote economic growth and global welfare. This dilemma is traduced in the impasse of the recent Doha Round, but it is already time for more ideas to be brought and paradoxes to be resolved. The current challenge faced in this study becomes then to conciliate the SDT, Reciprocity the development concerns. At the end, preferential systems do not go against liberalization. Instead, the SDT intends to graduate the liberalization process through fairness (development) and to enable, only afterwards, that seriously discussions regarding free trade and Reciprocity can be held regarding their full or, more plausibly, partial implementation.