Heart failure (HF) is a condition in which an abnormality in the function or structure of the heart leads to a decrease in peripheral perfusion. The most common causes of HF in newborns and infants are congenital heart defects, while in the older population it is acquired or recent arrhythmias, cardiomyopathies and myocarditis. The incidence of HF is about 1 child per 100,000 children. Symptoms and signs that characterize HF are dyspnea, prolonged feeding time and reduced volume of food consumed (in infants), and retardation in growth and development which is the primary sign of HF. The diagnosis is made on the basis of the clinical picture and laboratory findings, in which the emphasis should be on the biomarkers BNP and NT-proBNP, and troponin if there is a suspicion of the ischemic basis of HF. Imaging is the key method for showing changes in the structure of the heart. X-ray of the chest organs can reveal cardiomegaly, and the absence of cardiomegaly almost excludes the existence of heart failure. In order to confirm there is cardiomegaly, the cardiothoracic index should be used, which refers to the ratio of the size of the heart to the size of the chest. The cardiothoracic index in newborns must be greater than 60%, or 55% when talking about older children. Echocardiography is the most useful imaging method because it can be done an unlimited number of times, there is no harm to the patient and it provides a live image. Echocardiography is used to detect the cause, assess the hemodynamic status and evaluate reaction to therapy. According to the Ross score, the disease is classified into 4 stages depending on laboratory and clinical findings. HF therapy is primarily used to reduce symptoms and complications and improve the patient's quality of life. Primary therapy is drugs, the most common of which are diuretics, beta blockers, inotropic drugs and ACE inhibitors. In the final stages of the disease, ECMO and heart transplantation are performed.