In conclusion, plain-film radiography and the UGI series are useful, easily obtained tests for screening the pediatric UGI tract and differentiating between medical and surgical disease. Ultrasound continues to develop as an initial test for evaluation of the vomiting infant because of its reliability in diagnosing HPS. Endoscopy remains the superior method for diagnosis of mucosal diseases given the limitations of single-contrast barium studies and the newcomer status of ultrasound. Although scintigraphy is the most sensitive and physiologic imaging method for evaluation of gastroesophageal reflux, the UGI series and endoscopy currently play dominant roles in the evaluation of the child with "significant" GERD. CT, MR imaging, and endoscopy are secondary procedures because of their preparation, sedation, monitoring requirements, and cost. Each modality provides the radiologist a different perspective on pediatric UGI disease and therefore improves our ability to understand and diagnose abnormalities in the pediatric UGI tract.