Echocardiography is an essential examination in the diagnosis and treatment of cardiovascular disease as it noninvasively yields much information. In Japan, there has been an estimated increase of 9,000 adults with congenital heart disease every year from 1997 to 2007. In 2007, there were estimated to be about 409,101 adults with congenital heart disease (ACHD) in Japan. An increasing number of those with ACHD face lifestyle-related diseases, pregnancy-related problems, and cardiac dysfunction. However, there are few pediatric cardiologists engaged in the medical treatment of those with ACHD. Therefore, knowledge of echocardiography of ACHD is necessary for physicians and laboratory technicians. Although adults with congenital heart disease share the basic cardiac anatomical anomalies and physiology with the pediatric population, cardiac structures grow and evolve with the patients. Structural changes occur following surgical palliation and repair. Even without intervention during infancy and childhood, progression into adulthood can bring with it changes in ventricular mass, calcification or dysplasia of valves, and myocardial fibrosis. Many of these patients face further operations and interventions. They require lifelong medical care. Echocardiography is an essential tool for the diagnosis and follow-up of adults with congenital heart disease. In adults, it is often difficult to obtain much information with echocardiography, because adults with congenital heart disease have limited acoustic windows. However, it is possible to evaluate the primary form of ACHD by using a segmental approach, where it is possible to grasp the pathological state by identifying the issues involved in each of its states as the examination proceeds. In echocardiography of adults with congenital heart disease, it is important to organize the knowledge of the morphological characteristics of congenital heart disease, natural history, surgical methods, and postoperative history (complications, residuae, sequelae).