Bitcoin is the most famous cryptocurrency of our time. Since its foundation in 2008, it has been subject to a constant user growth and is also a frequently discussed topic in politics and legislation. Besides many advantages of this new currency, the public opinion on it is often overshadowed by a number of disadvantages. The missing authority, the high risk and the pronounced criminal use of this cryptocurrency are just a few points of criticism. Furthermore, criminal prosecution in the usual sense is not possible, since cryptocurrencies are more or less anonymous. Also, legal authorities have no power of control over accounts or transactions, which makes it much more difficult to track illegal money. The focus of this diploma thesis is to classify Bitcoin in terms of law and especially investigate the use of it in organized crime. For this purpose, the cryptocurrency Bitcoin is investigated, compared with fiat currencies and risks are also described. A classification in a legal sense based on the current legal situation of Austria and other countries is, besides a functional classification, an important part of this work. To take a closer look at the use of Bitcoin and other cryptocurrencies, a definition and consideration of organized crime in a general way is necessary. In doing so, different areas of organized crime are discussed, including the area of cybercrime, and the connection to Bitcoin is shown. As one of the most important factors of organized crime or criminal actions in general, money laundering is one of the main subjects of this thesis. Money laundering is observed in general as well as in detail, with a particular focus on the specific areas and methods. Money laundering in the virtual world and the use of Bitcoin as new option in money laundering is of great importance in this thesis.