PURPOSE: Intestinal duplication is a rare congenital anomaly that may be found anywhere from the mouth to the anus. The clinical presentation varies depending on the anatomic location or the size of the duplication, and the presence of the ectopic gastric tissue. The aim of this study was to analyze the clinical characteristics, the diagnostic and therapeutic methods, the location, the anatomic type and the associated anomalies of intestinal duplication. METHODS: We reviewed the medical record of eighteen patients with duplication of the alimentary tract and these patients had been treated at Kyungpook National University Hospital from July 1995 through October 2007. RESULTS: There were 9 boys and 9 girls. Their ages ranged from 3 days to 15 years. The most common symptom was abdominal pain. The duplicated segment acted as a leading point of intussusception in 3 cases. Two patients had melena. The duplications were cystic in fifteen cases and three others were tubular. In twelve cases, the lesions were located in the ileum; two other cases were located in the anal canal, one other was located in the in the transverse colon, another was located in the transverse and descending colon, one was located in the in the duodenum and one was located in the jejunum. Ultrasonography, computed tomography and barium enema were helpful as diagnostic tools. Three cases were diagnosed by prenatal ultrasonography. Associated anomalies were documented in four cases. All the patients underwent surgery. A duplicated lesion was lined with ectopic gastric mucosa in only one case. One patient still suffers from short bowel syndrome as a result of volvulus. CONCLUSION: The early operative treatment of intestinal duplication is safe and effective to prevent complications. In patients with intussusception, duplication should be considered as one of the causes of the leading point of intussusception.