This article discusses the role of OLAF in the fight against fraud in the European Union (EU) by examining (1) its powers and capacity to coordinate the activities of anti-fraud agencies in the twenty seven member states and (2) the constraints which prevent OLAF from operating in a more effective manner. It also analyses OLAF’s relationship with other transnational agencies such as Eurojust and Europol and highlights the degree of fragmentation which exists among the many actors involved in the fight against fraud, a fragmented legal approach and the difficulties this presents in attempting to police sophisticated transnational frauds. The effect of EU expansion on this situation is considered and the support offered to new member states who have been asked to bring their anti-fraud structures up to the standards of existing members within a very short period of time is also examined. The efforts of Romania in seeking to build up anti-fraud structures and systems are discussed in some detail. This article concludes that despite the best efforts of the actors involved, a fragmented legal system and institutions have hampered the fight against fraud in the EU.