Radiofrequency catheter-mediated ablation is a recently developed technique of achieving cure of certain rhythm disorders, notably supraventricular tachycardia. In less than a decade, it has evolved from a theoretic concept to first line therapy for many patients, including those in the pediatric age group. The most common types of arrhythmias amenable to catheter ablation include supraventricular tachycardia due either to an accessory pathway or A-V nodal reentry and atrial fibrillation with a rapid ventricular response refractory to medical therapy. Before the development of the technique, the only therapeutic options included either lifelong antiarrhythmic drugs or open heart surgery. The initial experiences with catheter ablative techniques used direct current shocks of up to 400 J, delivered to an intracardiac catheter from a standard defibrillator. This energy source has largely been replaced by radiofrequency current because of the substantially lower morbidity and greater efficacy. The treatment of patients with these tachyarrhythmias is evolving from a palliative approach to a curative one. With the current worldwide experience, complications are relatively rare and do not appear to differ from those associated with routine electrophysiologic testing or cardiac catheterization. The success rate is high, usually exceeding a 90% efficacy, but is dependent on the skill and experience of the operator. The technique, arrhythmias amenable to treatment, and the nursing implications before, during, and after the procedure are discussed in this article.