Catheter ablative techniques have introduced an exciting new chapter of interventional therapy for patients with drug-resistant cardiac arrhythmias. A variety of techniques are presently available, and proper choice depends on proper localization of the tachycardia focus and mechanism of the arrhythmia. These techniques should be performed only in laboratories with personnel experienced in invasive electrophysiologic procedures. Over the past 5 years, we have learned that catheter ablation of the AV junction for patients with drug-resistant supraventricular tachycardia has replaced the need for surgery in these patients. In addition, preliminary experience suggests that the catheter technique may be highly effective for patients with tachycardia incorporating a posteroseptal accessory pathway. The precise role of catheter ablation for patients with atrial or ventricular tachycardia has not been clearly defined.