Abstract: An omental cyst is a very rare pathology, especially in small infants. Children generally present with abdominal distention with or without a palpable mass. The mass may be huge, simulating ascites. The most common presentation in children is that of a small-bowel obstruction. The differential diagnosis includes intestinal duplication cyst, ovarian, choledochal, pancreatic, splenic, or renal cysts, hydronephrosis, cystic teratoma, hydatid cyst, and ascites. We describe the clinical presentation, imaging features, surgical treatment, and postoperative course of a 21-month-old female infant with a congenital giant omental cyst. This entity is extremely rare but should be included in the differential diagnosis in similar cases.