Money laundering is an illegal or criminal act that the whole world is facing. It represents an action through which money and cash equivalents are directed to activities for which the funds are not intended. The simple definition says that money laundering can be defined as showing funds as if they come from one source when they come from another source. Money laundering is the "cleansing" of money acquired through illegal activities and its inclusion in the regular cash flow in trade or any other sector. This process takes place through three defined phases - laying, lying down and integration. Money laundering is increasingly present in the banking system, which is reflected in a large number of identified cases throughout history and recent times, which is why various mechanisms have been created to combat money laundering. The paper explains the concepts of money laundering and money laundering prevention systems, the historical development of money laundering problems, the mechanisms of combating money laundering, and the influence of the human factor on the instruments. Practical examples show the ways of money laundering in the world and the Republic of Croatia and the effectiveness of verdicts and fines against banks. The survey showed how familiar people from the world of finance are with the concept of money laundering and ways to combat this illegal activity.