The WCO recently conducted a workshop in Bangkok for Thai Customs and tax departments on the topics of Customs valuation and transfer pricing. Following a series of regional events based on this format, this was the first national workshop to bring together Customs and tax officials to discuss these overlapping issues. The first day of the workshop, under the sponsorship of Japan (CCF/JAPAN) and Thai Customs, was devoted to Customs valuation matters. Facilitators from the WCO Secretariat, Japan Customs and New Zealand Inland Revenue covered a number of technical issues and recent instruments issued by the Technical Committee on Customs Valuation on subjects such as third party royalties, assists and business design documentation. During the next three days, officials from Thai Revenue and Excise departments joined the group. Sessions were held on Customs valuation and transfer pricing to deepen participants understanding of the two regimes and how they interacted. Case studies were examined to demonstrate the possible use of transfer pricing data by Customs as evidence when determining whether or not the declared Customs value in a related party transaction had been influenced by the relationship between buyer and seller. On the final day, a panel session was arranged featuring representatives of PricewaterhouseCoopers and the University of the Thai Chamber of Commerce to discuss issues raised during the workshop from the business perspective.