Unintentionally retained textile foreign bodies in the abdomen after laparotomy is a serious medical error, with unknown incidence which can lead to severe complications. We present the case of a 24-year-old woman with a retained surgical sponge migrated into the jejunal lumen and causing an intestinal obstruction. Removal of the foreign body required repeated laparotomy and segmental resection of the affected intestinal loop. The article provides the analysis of the imaging diagnostic results, as well as possible reasons that led to the foreign body being left unintentionally. Reliable reduction of incidence and severity of consequences after retention of textile surgical objects in the abdomen can only be achieved through improved standards of patient safety, including careful sponge counting and the routine use of materials with radiopaque markers.