The population of adult patients with congenital heart disease(CHD) has increased dramatically because of improved survival of infants and children with CHD. There are still a substantial number of adults with unrepaired CHD. Many adult patients do not know the possible problems of their disease such as ventricular dysfunction, arrhythmia, and what they should pay attention to. They often consider themselves "cured" or "healthy" if only they don't have overt symptoms, and visit hospitals only after deterioration of their problems. Some patients are neglected because they cannot be corrected surgically although careful medical support can improve their survival and quality of life. It is, therefore, essential that the patients, their families, and physicians understand the potential problems of CHD and need for regular follow-up. In this paper we will take a brief review for common medical problems of repaired or unrepaired CHD and also mention a few specific diseases which are common in adults.