PURPOSE: To analyze delayed diagnosis, we collected date on pediatric and adolescent patients who had been admitted to the Emergency Department with injuries due to minor trauma METHODS: We retrospectively analyzed the age distribution, trauma mechanism, time interval for each affected body region at delayed diagnosis, hospital stay, and outcome for 161 pediatric and adolescent patients who had been admitted to the Emergent Department of Gachon University Gil Hospital from January 2006 to September 2008. RESULTS: The incidence of delayed diagnosis in pediatric and adolescent trauma was 11.8% in our retrospective review of 161 pediatric and adolescent patients. Lengths of hospitalization were longer in patients with delayed diagnosis (p<0.05). Patients with delayed diagnosis were more often transferred to other hospitals than patients with non-delayed diagnosis (p<0.05). The time intervals for each different affected body regions at delayed diagnosis were significantly different, but the hospital stays were not. There were no statistical significance to age on affected body region. CONCLUSION: From this study, we found that admission result and hospital stay were statistically significant differences between the delayed-diagnosis patient group and the non-delayed-diagnosis patient group. Finally, we must follow up pediatric and adolescent patients with minor trauma, closely considering missed injuries.