The purpose of this study is to evaluate the feasibility, advantages/disadvantages of patient-controlled sedation (PCS) compared to anesthesiologist-controlled sedation (ACS) during neurolytic pain block and regional anesthesia. Forty patients were divided randomly into two groups of 20 patients each. Group 1(ACS) received 0.01 $mg{cdot}kg^{-1}$ intravenous midazolam and 0.5 ${mu}g{cdot}kg^{-1}$ fentanyl intravenously by anesthesiologist just before, 30, and 60 minutes after the procedure to acheive sedation; Group 2 (PCS) patients self-administered a mixture of midazolam (0.4 mg) and fentanyl ($20{mu}g$) using a syringe type infusion pump (Terumo, Japan) to acheive sedation. Considering the dermographics of patients, the types and durations of procedure performed, the level of average sedation the comfort level were similar in both groups. But the doses of midazolam and fentanyl administerd in group 2 were smaller than those in group 1 (p<0.01). Patients in PCS group showed their level of sedation more proper than did those in ACS group. However, patients in ACS group rated their level of comfort higher than did those in PCS group. The findings of this study indicate that PCS using a combination of midazolam and fentanyl is a fafe and effective technique. More studies are, however, needed to determinc the best choice of drug(s), doses, lock-out intervals, and possible use of continuous infusion with patient-controlled sedation.