In clinical practice, I often encounter worried parents of children who are told that a heart murmur has been detected during a health checkup and come to me with anxiety to make a decision. In fact, murmurs can exist in the heart without structural abnormalities and are more common in children, more than 80% of whom have had a heart murmur in early childhood. These murmurs, also known as functional murmurs (or physiologic murmurs, harmless murmurs), are more pronounced in children after exercise, when they are emotionally excited, or when they have a fever. The only way to identify these murmurs is by multiple auscultations under the guidance of a pediatric cardiologist and in conjunction with an electrocardiogram, chest x-ray and echocardiogram. If a child presents with clinical symptoms, a loud murmur or conduction to other parts of the body, cyanosis, and abnormalities on the ECG or chest radiograph, he or she should be alerted to the presence of a pathologic murmur to avoid delaying treatment.