BACKGROUND: Epidural infusions usually comprise a local anesthetic, an opioid, or more commonly, a combination of the two, to minimize individual doses and to reduce unwanted side effects. The aim of this study was to compare analgesic and side effects of epidural infusion with 0.2% ropivacaine alone and in combination with 4 microgram/ml fentanyl after total abdominal hysterectomy. METHODS: Forty healthy total abdominal hysterectomy patients under general anesthesia with postoperative analgesia by continuous epidural infusion were randomly allocated into Group I; 0.2% ropivacaine alone (n = 20) or Group II; 0.2% ropivacaine and 4 microgram/ml fentanyl (n = 20). We assessed the visual analogue scale (VAS, 0 = no pain, 10 = worst pain), frequency of supplemental analgesics, side effects and patients' satisfaction of the result. RESULTS: The VAS and the frequency of supplemental analgesics were significantly lower and fewer in Group II compared to Group I. The incidence and severity of side effects were no differences between two groups. The satisfactions of patients were significantly higher in Group II. CONCLUSIONS: For postoperative analgesia, the epidural infusion of 0.2% ropivacaine with 4 microgram/ml fentanyl provided better analgesia than 0.2% ropivacaine alone.