BACKGROUND Flexible bronchoscopy could be an uncomfortable examination for some patients. The purpose of this study was to examine the patient characteristics associated with "patient satisfaction" with sedation during flexible bronchoscopy. METHODS Fifty-two patients undergoing diagnostic flexible bronchoscopy were divided into 2 groups. Group A (n=44) comprised patients who felt that the sedation was satisfactory, and group B (n=8) comprised patients who felt otherwise. All patients were given midazolam to maintain Ramsay sedation scores of 2 to 3. We measured blood pressure, heart rate, respiratory rate, oxygen saturation, and bispectral index scores (BIS) every 5 minutes during bronchoscopy. Adverse events were also recorded. RESULTS There were no significant differences between the 2 groups in terms of age, height, weight, blood pressure, heart rate, respiratory rate, oxygen saturation, duration of flexible bronchoscopy, or doses of lidocaine and midazolam. The BIS was significantly lower for group A than for group B. Adverse events that would lead to aborting the procedure were not encountered. CONCLUSIONS We suggest that the BIS value during flexible bronchoscopy is associated with the satisfaction of patients and they may be able to predict patients' satisfaction.