The COSO model (Committee of Sponsoring Organization of the Treadway Commission) The American senator TREADWAY, the founder and developer of this model, initiated an important research over internal control and its role in the organizations life, creating in USA the “Treadway commission”, on which recommendation the Organizations Sponsoring Committee was created, known nowadays as COSO. It has reunited the competences of professionals from the external audit, internal audit and big American corporations and elaborated a paper entitled “The code of the internal control”, paper which defines what should be understood from the internal control and concludes thatthis has nothing to do with known systems of inspection and verification. The definition of the internal control concept is still a problem which generates controversies, but its tendencies are to accept, internationally, the same sense of the term “internal control”, which means, first to detain the control and then to check. In the complex assembly of means and practices which any entity uses them in order to administer as best its activities, so it can reach the pre-established objectives, COSO, through the elaborated frame of control, has induced a certain order in this domain. Hence, the definition given by COSO to the internal control in 1992 is still good for the time being: The internal control is a process implemented by the Administration Board, management and personnel of an organization destined to offer a reasonable assurance to objectives accomplishment