Study objective: To investigate the effects and optimal concentration of chloroprocaine for epidural analgesia after lower limb orthopedic surgery. Design: Prospective, randomized, observational, multicenter clinical study. Setting: Operating room, postoperative recovery area, university hospital. Patients: One hundred and twenty patients from 4 hospitals were enrolled and randomized into 5 groups after lower limb orthopedic surgery under epidural anesthesia with lidocaine. Interventions: Epidural chloroprocaine mixed with 0.4 mu g/mL fentanyl was administered via a patient controlled analgesia pump at the concentration of 0.6%, 0.8%, 1.0%, 1.2%, or 1.4% after the surgery. Measurements: Systolic blood pressure, heart rate, visual analog score at rest and during activity, as well as the Bromage score at 0 minute, 30 minutes, 1 hour, 2 hours, 4 hours, 8 hours, 24 hours, and 48 hours after the surgery were recorded and compared. Use of morphine and incidence of adverse effects were also recorded. Main results: Patients given 1.2% chloroprocaine showed the lowest visual analog score compared with other groups. There was no significant difference in the Bromage score among 5 groups. The Bromage score returned to 0 in 89.7% of the patients 48 hours after surgery. No difference in postoperative morphine usage, blood pressure, or heart rate was found among 5 groups. Conclusions: Epidural 1.2% chloroprocaine with 0.4 mu g/mL fentanyl could generate proper analgesic effects with little influence on mobility in patients undergoing lower limb orthopedic surgery. In addition, it could generate a good sense and movement separation, facilitating the early functional training. 2016 Elsevier Inc. All rights reserved.