Objective: The objective was to determine the dosing, efficacy, and side effects of the nonselective β-blocker carvedilol for the management of heart failure in children. Study design: Carvedilol use in addition to standard medical therapy for pediatric heart failure was reviewed at 6 centers. Results: Children with dilated cardiomyopathy (80%) and congenital heart disease (20%), age 3 months to 19 years (n = 46), were treated with carvedilol. The average initial dose was 0.08 mg/kg, uptitrated over a mean of 11.3 weeks to an average maintenance dose of 0.46 mg/kg. After 3 months on carvedilol, there were improvements in modified New York Heart Association class in 67% of patients (P = .0005, χ² analysis) and improvement in mean shortening fraction from 16.2% to 19.0% (P = .005, paired t test). Side effects, mainly dizziness, hypotension, and headache, occurred in 54% of patients but were well tolerated. Adverse outcomes (death, cardiac transplantation, and ventricular-assist device placement) occurred in 30% of patients. Conclusions: Carvedilol as an adjunct to standard therapy for pediatric heart failure improves symptoms and left ventricular function. Side effects are common but well tolerated. Further prospective study is required to determine the effect of carvedilol on survival and to clearly define its role in pediatric heart failure therapy. (J Pediatr 2001;138:505-11)