The topic of this master thesis is frauds in Finance. In the beginning we define frauds, show the inception of frauds and different types of fraud, which are later thoroughly researched to show their exceptionalities. Because frauds are complex and harmful phenomena, special attention is given to consequences of different frauds and the system against frauds. The system against fraud is divided into institutions against frauds and laws that govern their activity. It is important to emphasize the importance of individual countermeasures against frauds. Individual countermeasures are both needed for companies and individual people. Second part of the thesis is dedicated to ponzi and pyramid frauds. It is important to define these frauds and show important distinctions between them. Thesis also shows a set of indicators for these frauds to help people detect and avoid them. Frauds like this cause significant social harm. Sadly, despite all previous examples these frauds still victimize many people. To explain this we have shown some important features of the psychological profile of both fraudster and victim that help to uncover reasons behind investing or organizing these types of frauds. The effect of the internet is also examined. In the last part of the thesis, Ponzi and Pyramid schemes, from different parts of the world and different time periods, are analyzed. Examples from Croatia are also researched.