Necrotizing enterocolitis (NEC) is a gastrointestinal condition usually found in premature neonates. Our case involves a full-term, 3-month-old male who was found to have pneumatosis after surgical repair of congenital cardiac defects. After cessation of enteral feeds, nasogastric tube decompression, and broad-spectrum antibiotics, breast milk was reintroduced 8 days after his procedure. Hematochezia developed, but repeat abdominal X-rays were normal with benign abdominal examinations, stable vital signs, and improved laboratory findings. Although feeds were slowly restarted with an amino acid-based formula, hematochezia persisted. Meckel's scan was negative, and Computerized Tomography revealed diffuse bowel inflammation. Esophagogastroduodenoscopy and flexible sigmoidoscopy were performed for further evaluation which showed stricture and ulceration at the descending colon. This procedure was complicated by perforation with subsequent resection of this segment and diverting ileostomy. Due to the risk of complications, it is suggested to wait at least 6 weeks from acute events such as NEC before performing an endoscopy.