In recent years, several research projects on barriers to inter-municipal cooperation have been implemented in the Czech Republic and abroad. However, the research results reflect the respective local and regional specificities and the results and conclusions are therefore diametrically different depending on the specific conditions in the country. The main goal of the paper is to analyse uneven socio-economic development of the municipalities in the South Bohemian Region on the example of the development of cooperation among the municipalities of the South Bohemian Region in relation to the economic background of the municipalities. When assessing the budget-related aspects of the municipality, it is not possible to prefer and take into account only the revenue side, it is also necessary to emphasize the expenditure side. In our case, we use what is called the self-financing rate (the share of own revenues in the current expenditures of the municipality). There is a hypothesis that municipalities with a higher rate of self-financing tend to get less involved in cooperation of municipalities, i.e. the higher the rate of self-financing, the lower the level of cooperation of municipalities. Economically stronger municipalities have no reason/interest to unite their forces with other entities in order to solve problems of regional development. The theoretical part of the work deals with searching for knowledge related to the issue of regional development and cooperation of municipalities and introduces individual methods, which are then applied as part of the analysis of municipalities. The author researched cooperation of municipalities between 2007 and 2020. However, in spite of the results of the graphical analysis, the above-mentioned hypothesis was not confirmed.