Brunner's glands consist of submucosal mucinsecreting glands, which are located in the duodenum (1). Brunner's gland hyperplasia (BGH) is usually asymptomatic. A few cases causing obstruction, hemorrhage or intussusceptions in adults have been reported in the literature (2). We report a case of a 12-year-old boy with BGH presented with duodenal obstruction.A 12-year-old boy was admitted to our emergency department with significant vomiting and weight loss over the course of one week. On the present admission, physical examination revealed extensive abdominal tenderness, especially in the epigastric region. An upper endoscopy showed mild esophagitis, completely open pylorus and considerably widened bulb. The mucosa seen in the intersection between the first and second part of the duodenum was edematous and hyperemic, and the instrument did not pass through at that level because of severe narrowing (Figure 1). Barium examination of the upper gastrointestinal tract revealed that the stomach and the first part of the duodenum were distended, passage through the second part of the duodenum was delayed, and retrograde filling of the stomach was observed. Histological examination revealed BGH. Lobules of Brunner's glands were extended into the lamina propria and were separated by delicate fibrous septa ( Figure 2). The cells constituting the glands were cytologically bland and showed no mitotic activity. An antral biopsy specimen was negative for Helicobacter pylori, and serum gastrin level was within normal limits. An abdominal computed tomography was performed, which showed an enlarged stomach and bulb, but no masses were detected. According to the subsequent assessment made together with pediatric surgery and radiology, the patient un-