Abstract Background: Subcutaneous implantable cardioverter defibrillators (S-ICDs) avoid complications secondary to transvenous leads, but inappropriate shocks (ISs) are frequent. Furthermore, IS data from patients with Brugada syndrome (BrS) with an S-ICD are scarce. Objective: We aimed to establish the incidence, mechanisms, and predictors of S-ICD in this population. Methods: We analyzed the clinical and electrocardiographic characteristics, automated screening test data, device programming, and IS occurrence in adult patients with BrS with an S-ICD. Results: Thirty-nine patients were enrolled (69% male, mean age at diagnosis 46±13 years, mean age at implantation 48±13 years). During a mean follow-up of 26±21 months, 18% patients experienced IS. Patients with IS were younger at the time of diagnosis (36±8 versus 48±13 years, p=0.018) and S-ICD implantation (38±9 versus 50±23 years, p=0.019) and presented with spontaneous type 1 Brugada ECG pattern more frequently at diagnosis or during follow-up (71% versus 25%, p=0.018). During automated screening tests, patients with IS showed lower QRS voltage in the primary vector in the supine position (0.58±0.26 versus 1.10±0.35 mV, p=0.011) and lower defibrillator automated screening score (DASS) in the primary vector in the supine (123±165 versus 554±390 mV, p=0.005) and standing (162±179 versus 486±388 mV, p=0.038) positions. Age at diagnosis was the only independent predictor of IS (hazard ratio=0.873, 95% confidence interval: 0.767-0.992, p=0.037). Conclusion: IS was a frequent complication in patients with BrS with an S-ICD. Younger age was independently associated with IS. A more thorough screening process might help prevent IS in this population.