Introduction and objectives. The findings of the 2006 Spanish Catheter Ablation Registry compiled by the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias are presented. Methods. As in previous years, data were collected in two ways: retrospectively using a standardized questionnaire sent to electrophysiology laboratories by the Working Group on Electrophysiology and Arrhythmias, and prospectively from a central database. Each participating center selected its own preferred method of data collection. Results. Forty-eight Spanish centers contributed data voluntarily. A total of 6568 ablation procedures were recorded, averaging 139±75 per center. As in previous reports, the three most frequently treated conditions were atrioventricular nodal reentrant tachycardia (n=1881, 28%), accessory pathways (n=1628, 25%), and typical atrial flutter (n=1507, 23%). Atrial fibrillation was the fourth most common condition treated (n=540, 8%). The overall success rate was 92.2%, major complications occurred in 1.4%, and the mortality rate was 0.015%. Conclusions. In 2006, the number of ablation procedures recorded in the Spanish Catheter Ablation Registry continued to grow, with more than 6500 procedures now being registered. The success rate increased and there were fewer complications. Atrial fibrillation remains the fourth most common condition treated by catheter ablation at Spanish arrhythmia units.