Article 90 of the Act on the Nationwide Referendum, last amended on July 7, 2023, allows for nationwide elections and a referendum to be held on one day. However, the regulation contained in Art. 90 of the mentioned Referendum Act is incomplete, constitutionally questionable, and therefore highly imperfect. As practice has shown, the situation of simultaneous holding of elections and a referendum not only poses significant organizational challenges for the electoral administration, but above all does not guarantee compliance with the basic constitutional principles and standards of electoral law, for example it reduces the level of guarantee of the implementation of the electoral right (which includes the element of the need to take into account the vote of every voter), the principle of secrecy of voting, or transparency of financing of the election campaign and the separation of the election campaign from the referendum campaign. In this article the author tries to answer the question of what changes to Art. 90 of the Referendum Act should be introduced to ensure compliance of simultaneous votes ordered on its basis with the standards of free and fair elections.