Chronic heart failure (CHF) in children occurs mostly as a result of systolic dysfunction of the systemic ventricle or of congenital defects leading to large left-to-right shunts and pulmonary overcirculation. The ensuing symptoms and signs are similar in both cases, and include respiratory distress, poor feeding and growth, and hepatic congestion. Grading the severity of the symptoms accurately and reproducibly is important for studying CHF and the response to therapy. The Ross classification for young children and the New York Heart Association classification for older children are frequently utilized for such grading. The standard therapy for CHF in children consists of diuretics, to reduce cardiac preload and improve symptoms, and the maximization of nutritional support. The role of digoxin in treating CHF in children is controversial, especially regarding those children with pulmonary overcirculation where the function of the systemic ventricle is usually well preserved. As the importance of neurohomonal changes in the pathogenesis of worsening CHF is elucidated, newer medications aimed at counteracting such changes are becoming more important in the medical therapy of CHF in children. ACE inhibitors improve function and survival in adults with CHF, and they probably do the same in children with systemic ventricular dysfunction. It is less clear how effective they are in pulmonary overcirculation, but patients with high flow and low pulmonary resistance are most likely to benefit. In infants receiving treatment with ACE inhibitors, it is necessary to monitor for renal insufficiency or renal failure. β-Adrenoceptor blockade has also been established as an effective therapy for adults with CHF with beneficial effects on survival and left ventricular function. While data for the pediatric population are limited, early studies suggest that β-adrenoceptor antagonists (β-blockers) may work well in infants and children with CHF. Caution must be used by starting treatment with very low dosages of β-blockers and gradually increasing to the desired goals with close monitoring of blood pressure and heart rate. It is clear that larger multicenter trials are crucial to our ability to provide the most appropriate treatment for children with CHF. The demand for effective medical treatment will increase as more patients with palliated single ventricles survive surgery and then develop CHF from dysfunction of a hypertrophic and dilated single ventricle.