This paper assesses the effectiveness of non-tariff special and differential treatment (SDT) offered exclusively to the least developed countries by WTO agreements. SDTs are inefficient in at least four aspects. First, they are not easily accessed as they require a certain level of institutional capacity. Second, when accessible they either need to be complemented by other policy interventions or are offset by measures taken elsewhere. Third, some do not respond to LDC needs. Fourth, many are too vaguely defined to provide concrete benefits. Effectiveness can be enhanced by increased LDC ownership and improved policy coherence by trading and development partners. Special and differential treatment in WTO agreements: how have LDCs been differentiated? -- Special and preferential treatment and its use by the LDCs -- Assessing effectiveness (of what is being used) -- Trade capacity building: the integrated framework and its enhancements -- Concluding remarks -- Annex. Legal Texts of the WTO Adopted by the Uruguay Round of trade negotiations. Articles with reference to the least developed countries -- Annex 2. understanding on rules and procedures governing the settlement of disputes -- Annex 3. Trade Policy Review Mechanism (TPRM) -- Annex 4. Plurilateral trade agreements.