The cooperation of local government units (especially communes) has been present in contemporary world literature for a long time. It is of interest to representatives of various sciences (including praxeology, management, law, economy and finance, politics and administration). Against this background, the research on intercommunal cooperation in the countries of Central and Eastern Europe is more modest. The study, using the dogmatic-legal, historical-legal and empirical methods, examined and assessed the associations of local government units established in Poland for 30 years, which are the most institutionalized form of cooperation in local government. They are created in order to jointly implement public tasks, the effects of which are aimed at satisfying the basic needs of residents of local government units. The institutionalization of this form of cooperation manifests itself on many levels. The unions are separate legal entities, represented by their own bodies, they have their own organizational structure and their own budgets. Their close relations with the territorial self-government units that constitute them result primarily from taking over the implementation of public tasks and deriving significant income from contributions and membership fees. They also generate their own income, especially from fees for the services provided and the components of the technical infrastructure made available. Dynamically developing relationships can also be an important factor contributing to the development of regions.

The intended aim of the research was achieved, showing that despite several significant changes in legal regulations concerning associations of local government units, the interest in their creation has not decreased. Most of the registered unions have been operating for over a dozen years, so they have become a permanent form of effective cooperation in local government. Their durability is determined by an objective necessity resulting from the different level of development of individual local government units.