PURPOSE: This study aims to evaluate the efficacy and safety of sedatives for pediatric patients using noninvasive procedures. METHODS: We performed a prospective study in 446 (aged 1 month-21 y) consecutive pediatric patients undergoing sedation to study noninvasive sedation techniques from February to August 2007. We reviewed demographic data, sedative drugs, dosage, complications, and successful rates of sedation according to the underlying diseases. RESULTS: The overall successful rate of sedation was 435/446 (97.5%). The overall rate of successful sedation using chloral hydrate was 99.1% (420/424), and was 70.6% (12/17) and 60.0% (3/5) with ketamine and midazolam, respectively. Of the neurologic patients (n=172, aged 1 month to 21 years), 136 patients were sedated for EEGs, 5 patients for renal scans, and 31 patients for neuroimaging studies such as brain CT or MRI. All non-neurological patients (n=274, aged 1 month to 5 years) were diagnosed with urinary tract infection and sedated for renal scan. The overall success rate of sedation for this group was 99.6%(273/274). Atotal of 14 adverse events were observed (3.1%). Most adverse reactions were mild in severity and clinically insignificant. CONCLUSION: Using chloral hydrate alone has enough effect to sedate non-neurologic patients. However, neurologic patients in the severe course group, especially those suffering from intractable epilepsy, autism, or severe cerebral palsy, must be medicated with chloral hydrate 2 times at most; instead, injections of ketamine or midazolam in the early stage may result in a more promising outcome.