Introduction: referendums on amendments to the constitution held in 2022–2023 in Belarus and Uzbekistan raised a number of issues relating to public authorities organization and functioning. This brings about a research problem of the factors and reasons under development and implementation of these changes as well as the amendments impact on political process in the respective states (in particular, on the transformation of presidency and party systems). Objectives: to analyze the purpose of amending the Belarus and Uzbekistan constitutions with regard to the form of government and regulation of the political parties role and potential political consequences of the changes; to assess the further evolution of political regimes in the respective states in the context of maintaining their stability. Methods: the method of index analysis by A. Crowell – O. Zaznaev, the method of assessing the presidential powers by M. Shugart and J. Carey, the author’s typology of the presidency models. Results: in Belarus, the right to determine the main directions of policy was assigned to the newly created supreme authority – the All-Belorussian People’s Assembly, and in Uzbekistan this right has been retained by the President. At the same time, the formal powers of the Belarus President have strengthened, while in Uzbekistan the president remained constitutionally “weak”. As a result of the changes, the President of Belarus has been deprived of a number of important powers; however, due to the fact that the current president is likely to use the constitutional right to head the People’s Assembly, his constitutional powers will expand significantly while maintaining informal powers. The party systems of Belarus and Uzbekistan, despite the different proportion of party member deputies in the parliaments, can still be attributed to the same “non-party” type. The amendments have not changed the form of government indices in both Belarus and Uzbekistan and these still differ from each other, but the models of power organization in these states are quite close. Conclusions: the main purpose of the amendments to the constitutions of Belarus and Uzbekistan in 2022–2023 was to strengthen the presidential power. The new legal framework is not only of formal importance, but will also determine the political systems functioning in both states for decades to come. They can play a special role in the power transfer to a new president, the extension of the current president powers or providing the ex-president with a special status in the political system.