In a previous study, we assessed the efficacy of a continuous fascia iliaca compartment block (FICB) in reducing the pain at thigh autograft skin donor sites. However, a continuous local anesthetic infusion may cause toxicity or infection. In this prospective, randomized double-blind study, we compared the analgesic efficacy of FICB when given as a single shot vs continuous infusion during the 72-hour postoperative period up to the first dressing change (1dc). After ethical committee approval and informed consent, 81 adults (with 1% to 20% total burn surface area) who were scheduled for split-skin graft harvest procedures of the thigh underwent the FICB procedure before general or spinal anesthesia. Via FICB, patients received a bolus of 40 ml followed by 10 ml/hr consisting of either ropivacaine 0.2% for bolus and infusion (continuous, n = 27), or ropivacaine 0.2% for bolus and saline for infusion (single-shot, n = 27), or saline for both bolus and infusion (control, n = 27) until 1dc. Postoperative analgesia consisted of morphine via a patient-controlled analgesia device. We compared cumulative morphine consumption, static and dynamic pain scores, and side effects related to morphine or ropivacaine during the 72 hours up to 1dc. A single block had the same morphine sparing-effect as the continuous technique. Both techniques were equally effective in diminishing dynamic pain and reducing the side effects normally associated with morphine. However, patients receiving a single block experienced less residual paresia and were more satisfied with their pain-relief treatment than those who received a continuous infusion. A single-shot FICB is an easy, inexpensive, and efficient method for diminishing pain at thigh donor sites during a 72-hour postoperative period and has limited side effects and no residual paresia.