The article provides a brief description of the results of a study on the security of a regional economic system. The economic security of a region of the Russian Federation is a complex and multi-level system susceptible to both internal and external threats. In modern conditions, regions are a key resource for the country's development. Understanding vulnerability issues and addressing the challenges of ensuring the security of the regional economy are the basis for maintaining the stability of the national economy. The study identified the main threats to the security of the Russian regional economy. It was determined that the security of a region's economy depends on the diversification of its structure, strengthening the institutional environment, and successful adaptation to foreign policy challenges. The author developed a conceptual economic and mathematical model for maintaining regional economic security. It involves the integration of several sub-models reflecting the key aspects of the stability of the regional economic system: financial and budgetary, investment and structural, production (raw materials), and social. The proposed model can be applied by regional authorities of the Russian Federation in ensuring the security of the regional economic system and developing appropriate strategic decisions and management actions. The use of the cause-and-effect relationships described in the work should contribute to ensuring the sustainability of the socio-economic development of Russian regions.