Introduction. The issue of financial support for the development of urban agglomerations is one of the most relevant, since the timeliness and completeness of the integration processes financing largely determine the success in achieving the goals of creating agglomerations. Of particular importance is the budgetary and tax integration of local territories included in the single agglomeration space, since the current legislation establishes significant independence of local authorities in the formation of local budgets. Theoretical analysis. The article analyzes the approaches and processes used to include new rural areas in the already established system of urban agglomeration management using the example of the creation of “Greater Saratov” as part of the Saratov urban agglomeration. Legal and economic factors hindering the development of the agglomeration are identified. The features of the unified city budget formation and the budgetary powers of rural administrations as part of the agglomeration are studied. The problems of local taxation differentiation, taking into account the differences between rural and urban areas, are considered. Discussion of results. The study of the rural and urban areas integration features into a single socio-economic system revealed the advantages and problems of creating a unified budgetary and tax system in the agglomeration. The analysis carried out made it possible to substantiate measures for the urban agglomeration development, in terms of improving taxation and the budgetary process on its territory.