Financial frauds have been happening more and more often lately and with increasing consequences. Sometimes strong competition and the desire for higher profits lead management to be tempted to commit fraud that takes the form of misappropriation of assets, manipulation of financial statements, or corruption. Some of the manipulations in the financial statements are legal but should be careful because they easily turn into illegal ones. To prevent illegal behavior, a new branch of accounting, forensic accounting, has been developed and institutions such as OLAF, COSO and AFCOS have been established. Each type of fraud has its own signs and characteristics that warn that there is a danger of committing fraud, it is important to recognize and understand these signs so it is necessary to educate employees about early signals. According to world statistics, the largest number of frauds are committed by employees in the departments of sales, accounting, customer service, and procurement. This work is to describe some of the most well-known accounting and financial frauds that have led to a major financial meltdown. The aim of this work is to determine whether and how financial frauds such as Enron, Lehman and Madoff have affected the global financial crisis.