The differential diagnosis of abdominal pain in children can be challenging. We applied quantitative decisionmaking methods to this process and sought to determine if their use provided measurable benefit. Methods: After obtaining institutional review board approval, we recorded key elements of the history, physical examination, laboratory, and imaging evaluations along with the cost and the time spent in the emergency department (ED) for children presenting with abdominal pain. Initially, data were collected (group 1, n = 1366 patients) and then presented to the ED pediatricians. For subsequent patients, ED physicians received a sheet specific to that patient’s age and sex reporting the most common diagnoses and the elements of the evaluation that had proven most useful (group 2, n = 624 patients). We compared the difference in length of stay and costs before and after intervention, between study groups, by age groups, and separately by sex using a 2-factor analysis of variance. Results: The diagnostic workup cost less in boys aged 2 to 12 years after the intervention. In boys and girls older than 12 years, the cost trended lower. Discussion: This study demonstrates that ED physicians equipped with specific information were able to complete their diagnostic evaluation of children presenting with abdominal pain at a lower cost. The differential diagnosis of abdominal pain in children can be challenging. We applied quantitative decisionmaking methods to this process and sought to determine if their use provided measurable benefit. , laboratory, and imaging evaluations along with the cost and the time spent in the emergency department (ED) for children presenting with abdominal pain. Initially, data were collected (group 1, n = 1366 patients) and then presented to the ED pediatricians. For subsequent patients, ED physicians received a sheet specific to that patient’s age and sex reporting the most common diagnoses and the elements of the evaluation that had proven most useful (group 2, n = 624 patients). We compared the difference in length of stay and costs before and after intervention, between study groups, by age groups, and separately by sex using a 2-factor analysis of variance. Resul ts: The diagnostic workup cost less in boys aged 2 to 12 years after the intervention. In boys and girls older than 12 years, the cost trended lower. Discussion: This study demonstrates that ED physicians equipped with specific information were able to complete their diagnostic evaluation of children presenting with abdominal pain at a lower cost.