BACKGROUND: The pharmacologic interactions between propofol and adjuvant agents have increasingly been recognized as clinically important and the improved knowledge of these is being used to optimise the quality of total intravenous anesthesia. The aim of the present study was to investigate the effects of fentanyl, fentanyl-midazolam, and fentanyl-ketorolac as analgesic supplementations on the induction of propofol anesthesia with Diprifusor TCI. METHODS: Sixty ASA 1 patients undergoing elective diagnostic laparoscopy were randomly allocated to three groups equally according to injected adjuvant agents : group F, fentanyl 1 microgram/kg; group FM, fentanyl 1 microgram/kg-midazolam 0.05 mg/kg; group FK, fentanyl 1 microgram/kg-ketorolac 0.5 mg/kg IV before induction. Propofol target concentration of 4 microgram/ml was preset and unconsciousness with 3 min was considered as successful. Induction dose, time, success rate of induction, calculated and effective concentration, context sensitive decrement time when awakening concentration was 1.2 microgram/ml, vital signs and side effects were checked. RESULTS: Successful induction rate was 55% in the group F, 100% in the group FM, and 85% in the group FK (P< 0.05). Induction time and dose were significantly decreased in the group FM compared with the group F and FK. Calculated concentration, effective concentration, and context sensitive decrement time were significantly lower in the group FM than other groups. Injection pain score and postoperative pain score showed no differences between groups, but incidence of apnea was significantly increased in the group FM. CONCLUSIONS: Fentanyl-midazolam as a analgesic supplementation offered better quality of propofol induction using TCI, but showed increased incidence of apnea compared with fentanyl or fentanyl- ketorolac.