BACKGROUND: Midazolam or propofol has been used for the procedural sedation in children. However, the combined use of remifentanil have not been widely investigated. The purpose of this study was to evaluate the effectiveness and safety of remifentanil infusion with intravenous anesthetics during the central venous catheterization in children. METHODS: After institutional review board approval and written informed consent from patients' parent, 20 children planned central venous catheterization for chemotherapy were randomly assigned into two groups. All patients were infused with remifentanil 0.1microng/kg/min. In M group, 0.3 mg/kg of midazolam bolus was injected and 0.1 mg/kg bolus were injected intermittently if the sedation was inadequate. In P group, 1.0 mg/kg of propofol bolus and 150microng/kg/min were infused. 0.5 mg/kg of propofol was given intermittently if the sedation was inadequate. Hemodynamic variables, end-tidal CO2 (EtCO2), bispectral index score (BIS) were monitored throughout the procedure. RESULTS: There were no significant differences in hemodynamic variables, sedation and recovery times. Oxygen saturation (SpO2) in P group was significantly lower than that of M group at 15 min after the start of infusion. EtCO2 in P group was significantly higher than that of M group at 10 min after the start of infusion. Hypoxemia (SpO2< 90%) were occurred in three patients of P group. There was no significant difference in BIS among the groups. CONCLUSIONS: The combined infusion of remifentanil 0.1microng/kg/min with midazolam provided successful sedation without airway assistance during the central venous catheterization in children.