Owing to the EU-Turkish customs union, there is already a considerable degree of convergence between Turkey and the EU in the area of trade. In fact, Turkey is the only candidate country that has a customs union with the EU. At least with respect to the trade in goods, Turkey is almost part of the Single Market. The challenge of enhancing the present state of trade integration could be approached in two ways. First, the customs union could be deepened by refining the arrangements and addressing its shortcomings. Secondly, the degree of trade integration could be enhanced by incorporating areas such as services and agriculture – thus widening the customs union – which is also explored in detail. The paper concludes that the Turkish-EU customs union has been a technical success overall and functioned on a sound basis. Nevertheless, both parties should work flexibly towards eliminating trade defence measures and forging a more comprehensive framework of trade integration...