OBJECTIVE Fascia iliaca compartment block (FICB) has been shown to provide excellent pain relief in patients undergoing total hip arthroplasty (THA). However, the analgesic efficacy of FICB, in comparison with periarticular infiltration (PAI) for THA, has not been evaluated. This randomized, controlled, observer-blinded study was designed to compare suprainguinal FICB (SFICB) with PAI in patients undergoing THA via posterior approach. METHODS After institutional review board approval, 60 consenting patients scheduled for elective THA were randomized to one of two groups: ultrasound-guided SFICB block or PAI. The local anesthetic solution for both the groups included 60 mL ropivacaine 300 mg and epinephrine 150 µg. The remaining aspects of perioperative care, including general anesthetic and non-opioid multimodal analgesic techniques, were standardized. An investigator blinded to group allocation documented pain scores at rest and with movement and supplemental opioid requirements at various time points. Patients were evaluated for sensory changes and quadriceps weakness in the operated extremity. RESULTS There were no differences between the groups with respect to demographics, intraoperative opioid use, duration of surgery, recovery room stay, nausea scores, need for rescue antiemetics, time to ambulation and time to discharge readiness as well as 48 hours postoperative opioid requirements. The pain scores at rest and with movement also were similar at all time points. Significantly more patients in the SFICB group experienced muscle weakness at 6 hours after surgery. CONCLUSIONS Under the circumstances of our study, in patients undergoing THA, SFICB provided the similar pain relief compared with PAI, but was associated with muscle weakness at 6 hours postoperatively. BACKGROUND NCT02658240.