The incidence of persistent and permanent AF will likely continue to increase as the population ages and as patients with structural heart disease live longer. Many catheter-based ablation techniques have been developed to treat AF. This paper will review which of these approaches have been demonstrated to be effective for ablation of persistent and permanent AF. Because current approaches are associated with an unacceptable rate of ablation failure and proarrhythmia, further efforts are needed to develop better techniques and tools to safely, effectively, and permanently isolate the PV antra, to identify which sites are critical to the maintence of AF, and to create durable transmural linear lesions to interrupt intraatrial reentry.