Commercial law is an important part of jurisprudence, since it controls commercial or trading activities. It represents a complex of norms of private law, controls relations between enterprises, and contributes to the implementation of their business activities. Therefore, the main purpose of the work is to learn the hierarchy of the application of law sources in the private law code, as well as aspects of the use of the de legeferenda analogy. The questions of vertical structure, conceptual definition and subsequent application of sources of law are considering in the paper. It was analyzed the Commercial Code on the example of the Republic of Slovakia and the Czech Republic. It has been established that the legal system as a whole is reasonably considered to be a rational and moral method of regulating public life. It is found that the development of legal discipline requires the participation of research officers. Since this can be a major incentive for the legislation development in a broader perspective for the benefit of the national economy

Keywords: Slovak Commercial Code, political influence, obligation, judicial decision, legislator