Background: Delirium and agitation is a post anesthetic problem which interferes with children relaxation in recovery room. Agitation in recovery room can hurt to child and the nurse of recovery can not do his care in the best. Agitation in children that received sevofluran is more than halothan and isofluran and its because of rapid elimination of this drug. This drug has lower partition coefficient and rapid elimination. This agitation would be hard to control for the nurse of recovery. In our study we added ketamin to midazolam based oral premedication for reducing sevofluran–related delirium.Methods: In this randomized clinical trial study, 60 children aged 2-8 years who were undergoing general anesthesia for elective surgery in children's medical center in Tehran during 2011-2013 were included. The patients were allocated into groups: Group 1 (30 patients) received oral midazolam 0/5mg/kg, mixed with ibuprofen 10mg/kg, while Group 2 (30 patients) received a similar premedication mixture, in addition to ketamin 2mg/kg. Induction of anesthesia was carried out using sevoflurane and was maintained with sevoflurane 1.5-4%. The incidence and severity of pain, delirium score, recovery and extubation duration were recorded postoperatively. Findings: Vomiting shows no significant difference between both groups. Extubation time showed significant differences between both groups and its longer in ketamin group. Recovery time is similar in two groups. Pain score between two groups were significantly different and its less in ketamin group, although there was significant difference in delirium score between two groups, and it was better in ketamin group, especially after 30 minutes that most anesthetic drugs are eliminated from body. RN satisfaction was better in ketamin group (p<0.000).Conclusion: This study showed that adding a low dose of oral ketamin to midazolam-based sedation in children undergoing hernial repair reduced sevofluran-related delirium and agitation.