The paper investigates the effectiveness of trade preferences for LDCs. It confirms that overall trade preferences for LDCs increase LDC exports. However, it also finds that effectiveness differs across the nine providers included in the study (EU, US, Canada, Japan, Australia, New Zealand, Norway, the Russian Federation and Turkey) and that only a subset of LDCs is able to benefit from trade preferences. 1. Introduction -- 2. Literature -- 3. Measuring the impact of trade preferences -- 4. The augmented gravity model of trade and the trade preference-export link -- 5. Variables and main results.