Echocardiography is indispensable in medical examination for congenital heart diseases. Its ease of use by medical staff arises from its noninvasiveness. However, some misdiagnoses have come to be called “echo disease” and can cause misdirection in diagnosis and treatment. These pitfalls can result from human error, improper adjustment of the device, unsuitable view selection, and insufficient understanding of the characteristics, hemodynamics, or both, of the disease. With sufficient understanding and knowledge, however, these pitfalls can be avoided. We summarize possible causes of these pitfalls and provide useful examples.