Pediatric telephone triage programs have been initiated to reduce overcrowding of pediatric medical facilities, yet it is unclear what impact these programs have on reducing after hours room visits. This study used a decision analysis model and data from reference literature to investigate the effectiveness of this program and determine the factors that influence the results. The decision analysis model focused on a hypothetical group of children who were not undergoing ongoing treatment but developed symptoms or sustained injuries thought to require a nighttime visit to a medical facility. The model differentiated between urgent, semi-urgent, and non-urgent cases. Model parameters were estimated from the literature whenever possible. We estimated the difference in the number of children who received emergency medical attention, the number of semi-urgent cases in which attention was delayed, and the cases that did not receive medical care, between the telephone triage group and the control group. Telephone triage reduced the number of after hours visits by approximately 4%. There was no change in the number of semi-urgent cases for which medical care was delayed, and the number of semi-urgent cases that did not receive medical attention increased by three. The sensitivity analysis showed that increasing telephone triage use from 10% to 20% would reduce after hours visits by approximately 8%. We conclude that the benefits of this program to the region as a whole would outweigh the harmful effects. However, the effectiveness of telephone triage programs will be limited unless its usage is expanded.