BACKGROUNDS: This study was performed to determine the onset time and dose of intranasal midazolam used for preanesthetic sedation in children. METHODS: The children were randomly allocated to recieve one of three medications via the nasal route in a double blind manner. Group I: patients were given normal saline 0.2 ml/5kg, Group II: patients were given midazolam 0.2 mg/kg, Group III: patients were given midazolam 0.3 mg/kg. RESULTS: The cardiovascular and SpO2 changes were not significantly different among the patients of the three groups. The sedation score was greater in group II compared with group I from 5 minute after administration (1.9 vs 2.7, p<0.05). postanesthetic recovery score (PARS) was not significantly different among the three groups. CONCLUSIONS: It is suggested that intranasal midazolam (0.2 mg/kg) produces anxiolysis and sedation in children with rapid onset.