This paper addresses the problems of power supply reliability in a market environment. The specific features of economic interrelations between the power supply organization and consumers in terms of reliability assurance are examined and the principles of providing power supply reliability are formulated. The economic mechanisms of coordinating the interests of power supply organization and consumers to provide power supply reliability are discussed. Reliability of restructuring China’s power industry is introduced. Some reliability data is provided. The data shows that the reliability level has increased significantly in the past two decades. More and more measures are being applied to guarantee reliability of the restructured power systems. The reliability issues and challenges that are facing the Chinese power industry are considered The paper, then examines the evolution of power grids in India, the establishment of a regulatory framework, and operational philosophy in reliability aspects of long-, midas well as short-term (operational / outage) planning. Grid security, restoration, and mock trial for black start, etc. from the reliability angle are considered. Related issues for islanding operation to improve service reliability for Thailand’s Electric Power System are then analyzed.