This paper deals with the constitutionally guaranteed right to local and regional (regional) self-government, which is regulated in more detail by laws and by-laws. It is determined which units are local and which are regional self-government units. It deals with the City of Zagreb as a special, unique, territorial and administrative entity and the capital of the Republic of Croatia, as well as the specificities arising from its position. Management of organizations owned by the state, regional or local government is dealt with. What are the basic postulates of managing such organizations and what is the prevailing organizational form of such companies. An attempt is made to find an answer to the question why it is important for organizations that perform public activities to be fully or majority owned by the state, that is, under its continuous control and supervision. The importance of the role of the state, which is responsible for ensuring the continuous performance of certain activities, carries out supervision and control and, in the case of entrusting the performance of such activities to private sector organizations, appropriate regulation. The legal regulations that lay the legal foundations for establishing public organizations and entrusting certain activities to private sector organizations in the Republic of Croatia are listed. Communal activities, regulation and problems of performing certain communal activities in the Republic of Croatia are conceptually treated. Part of the work is devoted to types of organizations in the public sector, differentiation from private sector organizations, public services and their regulation at the level of the European Union. Conceptually, management is defined, its characteristics and how to apply the benefits of management in public sector management. The good and bad sides of the implementation of managerial reforms in public administration and the introduction of instruments and techniques of the private sector into the public sector and the consequences of the same are highlighted. The central part of the work is the application of the research to the study of Zagrebački holding d.o.o., a trading company owned by the City of Zagreb.