As a result of the liquidation of the Ministry of the Treasury, as of December 31, 2016, ownership supervision over 432 state-owned enterprises, so far exercised by this ministry, was transferred to 10 ministers. This change meant the decentralization of corporate governance in Poland. Over the next 5 years, numerous and significant changes took place in the bodies and entities supervising individual state-owned enterprises. The aim of the article was to answer the question whether the decentralization of corporate governance of state-owned enterprises and the numerous changes to the bodies and entities supervising individual companies in 2017-2021 contributed to its improved effectiveness. A critical analysis of the introduced legal regulations and literature related to the subject of the article leads to the conclusion that the decentralization of corporate governance and numerous changes to legal regulations concerning the location of the supervisory bodies of state-owned enterprises within the state structures did not contribute to the improvement of its effectiveness, as they did not result from substantive premises. Before the decentralization of corporate governance and during the implementation of changes, appropriate tools to assess these changes were not implemented. The real reasons for the introduced changes were political and resulted from the political struggle of individual factions within the ruling coalition, which wanted to supervise the largest possible number of state-owned enterprises. Therefore, the final assessment of the presented changes is negative.