© 2020, Kuwait Medical Association. All rights reserved.Objectives: To compare the analgesic efficacy of a femoral nerve block (FNB) and a fascia iliaca compartment block (FICB) in patients undergoing primary unilateral total knee arthroplasty (TKA) Design: Prospective randomised trial Setting: Orthopaedic operating rooms and services of Ankara Numune Education and Research Hospital, Turkey Subjects: Sixty patients of both genders, aged 40-70 years, with an American Society of Anaesthesiology physical status of I, II or III undergoing primary unilateral TKA for osteoarthritis, osteonecrosis or rheumatoid arthritis Interventions: TKA was performed under spinal anaesthesia on all patients with a 25G spinal needle and 3 ml of 0.5% bupivacaine. After surgery, the sealed envelope method was used to randomly assign patients to the FNB (Group 1, n = 30) or FICB (Group 2, n = 30) group, and blocks were performed using ultrasound guidance. Main outcome measures: The Visual Analog Scale (VAS) from 0 to 10 points measured at 1, 2, 8, 12 and 24 hours postoperatively. Motor and sensory blocks were also evaluated. Results: At all the measurement intervals, the VAS pain scores were higher in patients who had received FICB. At two and eight hours after surgery, patients in FICB group required additional analgesics at a significantly higher rate than those in the FNB group (p<0.05).The time to ambulation was longer in patients in the FNB group. Conclusion: In our study, both methods were found to be efficacious in providing satisfactory postoperative analgesia. However, patients who had FICB mobilised earlier and required earlier analgesic administration compared to the FNB group.