Sotalol is an antiarrhythmic medication that has properties of both a beta-blocker and a class III agent and has been used safely and effectively to treat arrhythmias of multiple mechanisms in pediatric patients. The purpose of this study was to review our institutional experience with sotalol in 45 patients with refractory arrhythmias and determine their long-term outcome. Patients responded to sotalol with 80% efficacy and a 22% incidence of adverse side effects. The mean sotalol dose was 116 mg/m2/day, and the average duration of therapy was 15.2 months. In spite of 80% efficacy, only 22% of patients remained on sotalol long-term. Sotalol was discontinued most commonly for either spontaneous resolution of disease or definitive cure by radiofrequency ablation. Other reasons for discontinuation of effective therapy included adverse side effects and arrhythmia control with either an antitachycardia pacemaker or another medication. One patient died while taking sotalol, but this case was considered a failure of treatment rather than an adverse side effect. Of the patients who still receive therapy, several have complex structural heart disease and require a combination of therapies, including sotalol, for adequate rhythm control.