OBJECTIVE Atrial arrhythmias have been reported in patients with Brugada syndrome. The aim of this study was to evaluate clinical predictors of atrial fibrillation (AF) in Brugada syndrome. RESULTS Patients diagnosed with Brugada ECG pattern were enrolled in the study. Type 1, 2, and 3 Brugada ECG pattern was found in 28, 56, and 31 patients, respectively. A total of 85 healthy age and gender-matched subjects were selected as a control group. Mean age, maximum P-wave duration (P(max)), P-wave dispersion (P(disp)), and left atrial dimension were not significantly different between patients and controls. There were no differences between P(max), P(disp), and left atrial dimension of the type 1, 2, and 3 Brugada patients. Spontaneous paroxysmal AF was detected in 15 of 28 type 1 Brugada patients (53%) and none of the type 2 and 3 Brugada patients. All 15 patients with AF had at least one episode of paroxysmal AF and none of the patients showed persistent or chronic AF. All 15 patients who had paroxysmal AF had previous life threatening cardiac events. In contrast, paroxysmal AF did not occur in type 1 Brugada patients without previous life threatening cardiac events. In multiple regression analysis, only the occurrence of previous life threatening cardiac events was a risk factor for paroxysmal AF (P = 0.0001). CONCLUSIONS It is concluded that the most important predictor of AF in Brugada syndrome is the occurrence of previous life threatening cardiac events.