The socio-economic progress favours the spread of phenomena of criminal character. Criminal activities bring an increase in the amount of the so-called dirty money, i.e. income generated by illegal activities. This income cannot circulate freely in the economy unless doubts concerning the legality of its origin are removed. Criminals seek therefore more and more sophisticated methods of money laundering, i.e. operations having as their objective the concealment of the true origin of illegal income and its provision with an appearance of legitimacy. The specific character of money laundering and the international scale of these operations exclude the classification of this phenomenon as common crime. Banks constitute this segment of the financial sector which is most vulnerable to the threat of becoming instrumental in the pursuit of criminal goals. On the other hand they are, among all the financial institutions, most experienced in combating money laundering. This is the reason why the article concentrates mainly on the role of banks in combating these illegal practices.

The system of money laundering prevention operates primarily on the legal framework, which unifies the procedures according to which states and their institutions collaborate in their fight against the influx of illegal funds. In the introductory part of the article, the author broaches the international regulations and standards that form the global system of prevention against the abuse of financial institutions for the purposes of money laundering. Parallelly, with international legal initiatives, organizations and programmes are being created to deal with this problem. The article describes Polish formal and legal actions, which contribute to the creation of the domestic system of money laundering prevention. The author, on the basis of personal experience resulting from many years' professional career in the banking sector, and also from making use of the experience gathered by particular banks in this respect, strives at making a practical assessment of the functioning of this system.