Although atrial tachycardias are relatively rare, their poor response to standard therapies, the suboptimal hemodynamic results of complete atrioventricular node ablation and pacer implantation, and their potential for serious hemodynamic effects make management difficult. Although their mechanisms are complex and divergent, catheter ablation has proven to be highly effective in management of atrial tachycardias. This article discusses arrhythmia mechanisms and therapeutic approaches by catheter ablation.