Objective To study the X-ray features and differential diagnosis of duodenal obstruction in neonates.Methods X-ray data of duodenal obstruction in 52 cases confirmed surgically were analyzed retrospectively.Erect abdominal plain films were done in each case;Upper gastric intestinal investigations(UGI) were performed in 28 cases,and barium or meglumine diatyizoate enemas were done in 36 cases.Results On the plain films,9 cases with single-bubble,29 with double-bubble,6 with tri-tubble,8 with multiple stepladder-like gas-fluid level in the bowel loops were noted.14 cases with completive obstruction and 13 cases with partial obstruction were found in UGI series.Malposition of the jejunum was seen in 8 cases among them.Abnormal location of cecum on barium enema was demonstrated in 30 cases,included 10 cases of microcolon.The etiology of duodenal obstruction included intestinal malrotation 34 cases,duodenal atresia 9 cases,duodenal stenosis 4 cases and anaular pancreas 5 cases.Conclusion Most cases of duodenal obstruction can be diagnosed with plain films combining with clinical materials.Differential diagnosis should be made by UGI series and barium enema.