Theoretically, the use of electroanatomical mapping systems may reduce radiation exposure, while three-dimensional rotational atriography (3DATG) may increase exposure. Anatomical representation and image registration using 3DATG are likely to be superior, but the net clinical benefit of either system is unknown. The purpose of this prospective randomized two-center study was to compare the procedural and clinical outcome of patients with atrial fibrillation (AF) treated by catheter ablation using either three-dimensional (3D) electroanatomical mapping (Carto) or 3DATG. From November 2007 to November 2008, 91 consecutive patients with AF (mean age 58 +/- 10 years; 63% paroxysmal AF, 37% persistent AF) from two centers (Bordeaux and Boston) were randomized to ablation using either 3DATG (44 patients) or Carto (47 patients). Of the 47 left atrial shells acquired with 3DATG, one was uninterpretable. There was no difference in total radiofrequency applications (72 +/- 23 vs. 79 +/- 33 minutes, respectively, P = .296), procedural duration (232 +/- 65 vs. 218 +/- 67 minutes; P = .335), fluroroscopic duration (75 +/- 28 vs. 67 +/- 26 minutes; P = .151), or radiation exposure (71,810 +/- 42,954 vs. 68,009 +/- 38,345 mGy cm(2); P = .719) between procedures performed with 3DATG or Carto. After a mean follow-up of 10 +/- 4 months, there was no difference in clinical outcome using either Carto or 3DATG concerning total arrhythmia recurrence (34% versus 38%; P = .668) or AF recurrence (20% vs. 15%; P = .555). Three-dimensional ATG-guided AF ablation has similar radiation exposure and procedural and outcome characteristics compared with Carto-guided ablation. The ease of use and accurate 3D representation of the left atrium make 3DATG a reasonable alternative to conventional 3D electroanatomical mapping systems, however, without advanced mapping functions.