BACKGROUND: In pre-school aged children, the occurrence of emergence delirium (ED) is increased after sevoflurane anesthesia. The purpose of this study was to evaluate if intravenous inducting agents such as propofol, ketamine or thiopental sodium affected the development of ED. METHODS: A total of 62 children between 3 and 6 years of age scheduled for elective tonsillectomy and adenoidectomy were divided into 3 groups in a double-blinded manner. Anesthesia was induced using one of the three drugs intravenously: 5 mg/kg of sodium thiopental, 1 mg/kg of ketamine or 2 mg/kg of propofol. Anesthesia was then maintained with sevoflurane. The development of ED was assessed in the post-anesthetic care unit. RESULTS: The propofol and ketamine group showed a significantly lower pediatric anesthesia emergence agitation (PAEA) score and a lower incidence of ED compared with the thiopental group. CONCLUSIONS: Propofol and ketamine decreased the development of emergence delirium when used as an induction agent.