Study objective: Comparison of ultrasound-guided lumbar plexus block (LPB) and suprainguinal fascia iliaca block (SIFIB) in patients undergoing total hip arthroplasty (THA). Design: Randomized equivalence trial. Setting: University Hospital. Patients: Sixty patients undergoing primary THA. Interventions: Patients were randomly allocated to receive ultrasound-guided LPB (n = 30) or SIFIB (n = 30). The local anesthetic agent (40 mL of levobupivacaine 0.25% with epinephrine 5 μg/mL) and block adjuvant (4 mg of intravenous dexamethasone) were identical in all subjects. Postoperatively, all patients received patient-controlled intravenous analgesia (morphine) as well as acetaminophen and ketoprofen during 48 h. Measurements: A blinded investigator recorded morphine consumption at 24 and 48 h as well as time to first morphine request, pain scores at 3, 6, 12, 24 and 48 h, incidence of adverse events, time to readiness for discharge, and length of hospital stay. The blinded investigator also carried out sensorimotor block assessment at 3, 6 and 24 h using a 10-point sensorimotor composite scale. Main results: No intergroup differences were found in terms of cumulative morphine consumption at 24 h (95% CI: −4.0 mg to 2.0 mg) and 48 h (95% CI, −5.0 mg to 2.0 mg) or time to first morphine request. Furthermore, pain scores were similar at all time intervals after 3 h. There were no intergroup differences in terms of composite sensorimotor scores at 3 and 6 h. However, SIFIB lasted longer than lumbar plexus block as evidenced by a higher composite score at 24 h. No intergroup differences were found in terms of complications. Compared with LPB, SIFIB was associated with shorter time to readiness for discharge (3 [1-4] vs. 2 [1-3] days; P = 0.042) and length of hospital stay (3 [2-5] vs. 3 [2-4] days; P = 0.048). Conclusions: For THA, no differences were found between LPB and SIFIB in terms of breakthrough morphine requirement and pain control. However, SIFIB resulted in a longer block and was associated with shorter time to readiness for discharge as well as decreased hospital stay.