Background: This purpose of this study is to compare the analgesic efficacy, occurrence of motor block and other side effects of 48 hr continuous postoperative epidural infusions with 0.125% ropivacaine with fentanyl or 0.15% ropivacaine with fentanyl. Methods: Forty patients undergoing Cesarean section were randomly allocated into two groups. Both groups received epidural injection of 2.0% lidocaine 19 ml and 0.75% ropivacaine 2-5 ml with fentanyl $50{mu}g$ for 20 minutes before surgery. Following surgery, a continuous epidural infusion using a two- day infusor was given for 40 minutes for post-operative pain control. Group 1 (n = 20) then received 0.125% ropivacaine and 6 ug/ml of fentanyl at a rate of 2 ml/h. Group 2 (n = 20) received 0.15% ropivacaine and 6 ug/ml of fentanyl at the same rate. Visual analog scales (VAS) for pain during rest and movement, sensory change and motor blockade were assessed for 48 hr after surgery. Results: There were no significant differences in VAS for pain during rest or movement. The incidence of side effects was similar in both groups. Conclusions: Using 0.125% ropivacaine with fentanyl via an epidural route provided similar pain relief and side effects as 0.15% ropivacaine with fentanyl.