Prevalence and prognostic value of conduction disturbances in patients with the Brugada syndrome (BrS) remains poorly known. Electrocardiograms (ECGs) from 325 patients with BrS (47 ± 13 years, 258 men) with spontaneous (n = 143) or drug-induced (n = 182) type 1 ECG were retrospectively reviewed. Two hundred twenty-six patients (70%) were asymptomatic, 73 patients (22%) presented with unexplained syncope, and 26 patients (8%) presented with sudden death or implantable cardioverter-defibrillator appropriated therapies at diagnosis or during a mean follow-up of 48 ± 34 months. P-wave duration of ≥120 ms was present in 129 patients (40%), first degree atrioventricular block (AVB) in 113 (35%), right bundle branch block (BBB) in 90 (28%), and fascicular block in 52 (16%). Increased P-wave duration, first degree AVB, and right BBB were more often present in patients after drug challenge than in patients with spontaneous type 1 ST elevation. Left BBB was present in 3 patients. SCN5A mutation carriers had longer P-wave duration and longer PR and HV intervals. In multivariate analysis, first degree AVB was independently associated with sudden death or implantable cardioverter-defibrillator appropriated therapies (odds ratio 2.41, 95% confidence interval 1.01 to 5.73, p = 0.046) together with the presence of syncope and spontaneous type 1 ST elevation. In conclusion, conduction disturbances are frequent and sometimes diffuse in patients with BrS. First degree AVB is independently linked to outcome and may be proposed to be used for individual risk stratification.