The paper presents a complex description of the system of Polish maritime law regarding vessel registration. There are four vessel registers in Poland: vessel register, Polish yacht register, administrative register, and fishing vessel register. The first three are regulated by the Polish Maritime Code of 2001 and the last by the Fisheries Act of 2004. Different registration bodies are responsible for the vessel registers. These are the Maritime Chamber, the Polish Yachting Association, the Maritime Office, and the Ministry of Agriculture. The author analyzed registration requirements and the basic procedural principles in the various registers. This is useful especially in light of the numerous changes which were implemented in the Polish Maritime Code following European Union accession. Some doubts are discussed regarding the implementation of EU Council Act 613/91 of 4 March 1991 to Polish law. The author also criticizes new legal solutions that give EU ship owners the right to the Polish flag despite the lack of a genuine link with Poland, the flag holder. The new Polish yacht register is described in detail. The responsibility for its implementation was given to a community organization and not to a state body. The author indicates many doubtful legal and organizational aspects of this register, especially with respect to the new decree of the Ministry of Infrastructure of 23 December 2004, which regulates yacht registers. The separate legal definition of the yacht in Polish maritime law seems to be questionable. It is defined as ' a marine vessel, which is the property of Poland, used exclusively for sport or recreational purposes with a hull length of up to 24 meters '. The administrative register, which registers vessels that are not covered by the two registers discussed above, vessels under construction on sea tests, and the fishing vessel register, is also discussed. It is not only of an administrative character but is one of the methods for limiting economic freedom in marine fisheries. The mutual relationships among these registers are also discussed in the paper.