The prognosis of congenital heart disease has dramatically improved due to advances in fetal diagnosis and improvement of surgical outcomes. Therefore, the number of patients with adult congenital heart disease now exceeds 400,000 (There are approximately 1.7 million patients with adult cardiovascular diseases.), nearly surpassing the number of pediatric patients. In contrast, pediatric cardiology specialists certified by the Japanese Pediatric Cardiology and Cardiovascular Surgery Society number about 500 people, which is a surprisingly small number compared with the approximately 13,500 specialists certified by the Japanese Circulation Society. Therefore, transition of patients with adult congenital heart disease to adult cardiovascular medical care will proceed inevitably. Under such circumstances, it is obvious that it is greatly harmful in clinical practice that echocardiography measurement is quite different between the fields of pediatric cardiology and adult cardiology. For example, in the case of measurement of left ventricular systolic function, it is common for left ventricular (LV) fractional shortening (FS) to be obtained from M-mode of the left ventricular short axis view, and then the LV ejection fraction (EF) calculated from Teichholz, etc., in pediatric cases. The reason why the biplane EF method is not used in children is that, first, there is little thought given to obtaining a four-chamber view including a true apex, resulting in unfamiliarity with obtaining an accurate four-chamber view; second, it is sometimes impossible to obtain a two-chamber view covered by the lungs, because the children usually cannot stop breathing when instructed. On the other hand, neither the pediatrician nor the cardiovascular physician has the deterministic methodology for measurement of right ventricular systolic function. Biplane EF cannot be used in the right ventricle because of its morphological complexity, and right ventricular FS in the short axis section cannot be applied. With regard to diastolic function, in childhood it changes dramatically at the developmental stage. Normal values of E wave, A wave, and early diastolic mitral annulus velocity (E′) itself are different, so it is not possible to simply use the same diastolic parameters for adults. Under these circumstances, taking into consideration changes in ventricular morphology and diastolic function at the developmental and aging stages, we should investigate standardized indices for systolic and diastolic function that can be used in both children and adults. Furthermore, how to spread awareness of standardization will be a crucial problem. In this chapter, we will present specific problems at present and explore what solutions are available.