The paper presents the roles played by regional development agencies in the territory of Serbia, which relate to the promotion of regional development and strengthening the competitiveness of the region. An overview of their establishment, operations, missions, and visions for the prosperity of the region is given. Attention is paid to the procedures that must be fulfilled for the regional development agency to receive accreditation and be able to operate successfully. The goal is to consider how regional development agencies influence the stimulation of the entire economy of the region. The interaction between regional development agencies and local self-government units, as well as their relationship with the economy, scientific and professional public, is emphasized. Conditions for evaluation are presented, as well as possibilities for further improvement of work efficiency. The importance of regional development agencies in strengthening cultural life and promoting interregional cooperation was presented. The focus is also on the interactions that exist between regional development agencies, but also on the relationship that the state level of administration has towards their work and operations.