The aim of this study was to determine the effect of thiopental sodium with that of midazolam-ketamine on relieving agitation after tonsillectomy in children. In a clinical trial, 50 children aged 5-10 years, candidates for tonsillectomy, were randomly divided into two 25-member groups. In the first group, thiopental sodium 5mg/kg/IV, and in the second group combination of midazolam 0.01 mg/kg/IV and ketamine 1 mg/kg/IV were used to induce anesthesia. The level of sedation was assessed after surgery with the Ramsay scale. There were no significant differences between the two groups in terms of heart rate, arterial oxygen pressure (PO2), and duration of anesthesia. The Ramsay sedation score was significantly higher in the thiopental sodium group than in the midazolam-ketamine group (P=0.01). Thiopental sodium can be more effective than the combination of midazolam-ketamine for controlling agitation after tonsillectomy in children.