Aim: To report the clinical courses of two patients with intestinal obstruction caused by duodenal web, who were diagnosed with this rare congenital anomaly at Clinical Hospital Center Rijeka in a span of 5 months. Case report: One of the patients was prenatally suspected to have duodenal obstruction due to ultrasonographic findings, while the other showed signs of obstruction by not tolerating oral intake from the second day of life (DOL). Ceasing enteral feeding, placing a nasogastric tube and introducing intravenous hydration and parenteral nutrition was performed as initial management. Abdominal ultrasonography, abdominal radiography, upper gastrointestinal contrast study and contrast enema were performed but showed no signs of obstruction. Both patients showed improvement in tolerating oral intake over the next few days. However, the first patient did not tolerate meals exceeding 15 mL of infant formula, and the second patient again did not tolerate any oral intake from the 15th day of life. A broad diagnostic workup was repeated but did not show conclusive evidence of obstruction regarding the first patient. Esophagogastroduodenoscopy found duodenal obstruction of unknown origin regarding the second patient. Laparotomy was performed on the 19th and 25th DOL, respectively. Duodenal web was visualized and excised in both patients following duodenotomy. Postoperative recovery was orderly with minor nonsurgical complications. The patients were discharged from hospital on the 21st and 36th postoperative day, respectively. Conclusions: Diagnosing a perforated duodenal web is often challenging because of possible intermittent nature of its symptoms. Exploratory laparotomy is sometimes required to reach diagnosis.