Internal hernia is the most common complication of Roux-en-Y gastric bypass. Although its incidence rate is low, hernias are becoming more common in patients undergoing bariatric surgery, with Petersen's hernia being one of the most frequent. The symptoms of internal hernia are variable, and the sensitivity of imaging methods is limited, resulting in a high rate of misdiagnosis of internal hernia by computed tomography. Surgery continues to be the first treatment option in patients presenting with clinical symptoms of obstruction after undergoing Roux-en-Y gastric bypass. Here, we present a case of intestinal obstruction secondary to Petersen's hernia after Roux-en-Y gastric bypass in the context of bariatric surgery.