AbstractEuropean Social Fund (ESF), being one of the oldest Structural Instruments of the European Union (EU) has to be implemented through projects, by public and private entities allover EU, according to the principle of “sound financial management”. But, are the Romanian ESF financed projects ready to comply to the “sound financial management” principle? The answer at this question may be delivered by a descriptive research on COSO's principles in ESF implementation context, followed by an explorative research on beneficiaries’ perception about how COSO's principles are implemented in their projects. The conclusions lead to a number of easy-recognizable and applied principles but also to some less applied principles, generating risks in ESF projects and in ESF implementation as a whole.