Background: Cesarean section (CS) is one of the most common surgical procedures in the world. Post-operative pain afflicts both mother and the newborn, especially the first 48 h after birth. Local anesthetics alone provide analgesia for a few hours. Increasing the duration of local anesthetic action is often desirable because it prolongs surgical anesthesia and analgesia. These achieve by adding fentanyl with buipvacine. Different additives have been used to prolong the duration of blockade and thus improve the quality of anesthesia and postoperative analgesia. Objective: To evaluate the efficacy and safety of ultrasound transverses abdomen plane block with bupivacaine, and the effects of adding fentanyl to bupivacaine for caesarian section. Patients and methods: This was a randomized, prospective, double-blind, clinical trial study conducted on 60 patients of American Society of Anesthesiologists (ASA) physical status I or II, scheduled for Cesarean deliveries were enrolled. The study was carried out at Al-Azhar University Hospitals (Al-Husein and Sayed Galal Hospitals), during the period from October 2018 to October 2020. They were divided into two equal groups: Group (A) patients were receiving ultrasound‑guided TAP block with 20 ml of bupivacaine 0.25% bilaterally, and Group (B) received ultrasound‑guided transversus abdominis plane block with 20 ml of bupivacaine 0.25% and 50 µg of fentanyl bilaterally. Results: The amount of diclofenac and nalbuphine consumed in 24 hours by both the groups were compared. The consumption of diclofenac and nalbuphine was significantly lower among the bupivacaine-fentanyl group. Baseline mean arterial blood pressure was comparable between the two study groups with no statistically significant difference. After 15, 30 and 45 minutes in postanesthesia care unit. The mean arterial blood pressure was significantly lower in group B, Bupivacaine combined 3 with fentanyl transversus abdominis plane block, compared to the Bupivacaine-only group. In the sub-sequent recordings, there was no statistically significant difference between both groups. Baseline heart rate was comparable between the two study groups with no statistically significant difference. Postoperative pain was evaluated through assessment of the mean visual analog scale score, at postanesthesia care unit, 0.5, 1, 2, 4, 6, 8, 12, 24 hours postoperatively. The mean visual analog scale scores indicated a significant reduction during recovery time in B group, at 2 and 6 hours postoperatively. However, no significant difference was observed in the mean of pain intensity between the two groups at other times. Conclusion: The addition of fentanyl as an adjuvant to bupivacaine in TAP block lowered postoperative pain scores, prolonged the time for first rescue analgesic, and decreased the postoperative nalbuphine consumption.