Gastrointestinal system duplications (GSD) are rare congenital anomalies. Eighty percent of GSD are diagnosed in children under the age of two. These lesions can occur anywhere from the mouth to the anus; however, the Jejunum is the less frequently affected area. GSD may be long and tubular but are more commonly cystic masses. The clinical presentation of GSD in adults is variable and, due to their rarity, often not initially suspected. In this case report, we present an ileal duplication in a 21-year-old male patient. Despite various radiological evaluations and laboratory analyses, the diagnosis was ultimately established through surgical intervention.