A 12-year-old girl presented with long-lasting intractable abdominal pain associated with a gastric diverticulum. The clinicopathologic features of this rare entity are discussed with emphasis on pathogenesis, diagnosis, and treatment. The authors emphasize that congenital diverticulum of the stomach should be considered in the differential diagnosis of abdominal pain in childhood. Surgical treatment consisting of simple excision of the diverticulum is warranted in cases presenting with long-lasting symptoms after failure of medical treatment.