Background:Pain is the leading cause that drives patients to receive total knee arthroplasty (TKA), it is also performed to improve joint mobility and quality of life. Peripheral nerve blocks with different modes have shown favorable control of perioperative pain associated with TKA. The development of new anesthetic medications has given more success in performing peripheral nerve blocks. Aim of the Study: To study the effect of fascia iliaca compartmental block in postoperative pain control in patients of TKA and comparing it to femoral nerve block. Patients and methods: Seventy adults who were undergoing TKA were included in this prospective randomized clinical trial. Patients receiving spinal anaesthesia were randomly allocated to either have an ultrasound guided fascia iliaca compartment block (FICB) or femoral nerve block (FNB). Results: Patients in FICB group had astatistically significant lower visual analogue scale score at PACU arrival than the FNB group with mean and standard deviation 1.00 ± 0.00 vs. 1.11 ± 0.32 respectively (p= 0.041). This was also seen after 6, 12 and 24 hours postoperatively. The time interval taken to ask for analgesia postoperatively was significantly later in FICB group than the other, with mean and standard deviation 9.86 ± 1.31 vs. 6.87 ± 0.92 respectively. There was also a significant decrease in total pethidine used in FICB patients.  Conclusion: The FICB can significantly decrease pain in the early postoperative period as well as after 6, 12 and 24 hours with a significant decrease in the usage of opioids.