The relationships between trade facilitation, trade flows, and capacity building are complex and challenging to assess, both empirically and in implementation. This paper measures and estimates the relationship between trade facilitation and trade flows in manufactured goods in 2000-2001 in global trade, considering four important categories: port efficiency, customs environment, regulatory environment, and service sector infrastructure. A gravity model is employed to estimate this relationship across 75 countries. The results suggest that both imports and exports for a country and for the world will increase with improvements in these trade facilitation measures. The gains from trade facilitation are predicted by using a simulation method, and compared across geographical regions, trade facilitation categories and who is undertaking reforms (domestic or partners). The total gain in trade flow in manufacturing goods from trade facilitation improvements in all the four areas is estimated to be $377 billion; all regions gain in imports and exports. Most regions gain more in terms of exports than imports, in large part through increasing exports to the OECD market. The most important ingredient in getting these gains, particularly to the OECD market, is the country’s own trade facilitation efforts.