The objectives of this study were to determine whether there was a correlation between bispectral index (BIS) and Ramsey Sedation Scale (RSS) in regard to the type of sedation and total intravenous anesthesia (TIVA) during colonoscopy procedures in children, and to assess the utility of ketamine and propofol combination (ketofol) for this kind of procedures at children’s age. In our prospective study, 40 ASA I-II patients, 3 to 17 years of age, were randomly divided into two groups of 20 patients each. After premedication with atropine and midazolam, sedation was induced with propofol and fentanyl in Group PF, whereas in Group PK propofol and ketamine were used for induction. Both groups were further divided into two subgroups depending on whether anesthesia was maintained with intermittent doses or continuous infusion of propofol. Ketamine and/or fentanyl were administered as bolus doses. Heart rate (HR), peripheral oxygen saturation (SpO2), RSS and BIS values of all patients were recorded every 5 minutes throughout the colonoscopy procedures. The strongest degree of correlation between RSS and BIS existed when sedation or TIVA was maintained by the boluses of propofol and fentanyl. The use of ketamine significantly reduced the doses of propofol and fentanyl. BIS can be monitored in all pediatric patients in whom sedation and TIVA are administered during colonoscopy, but the effect of different anesthetics on the EEG signal should be considered in order to adequately assess the depth of sedation and anesthesia.Key words: awareness, monitoring, child, anesthetics, endoscopy