Bochdalek hernia is the most common congenital diaphragmatic hernia. Its symptoms are normally diagnosed and treated during the neonatal period. Conversely, in adults it is usually asymptomatic and, as a consequence, this group is misdiagnosed. A case of a 64-year-old female patient with an uncommon incarcerated right-sided diaphragmatic hernia formed three years after a Roux-en-Y gastric bypass and a significant weight loss is reported. The importance of this abnormality as a complication of the bariatric surgery should be considered.Key words: Diaphragmatic hernia; gastric bypass; bariatric surgery