Background: Transversus Abdominis Plane (TAP) blocks provide postoperative pain relief after various abdominal surgeries. Recently, Erector Spinae Plane (ESP) block has obtained vast attention due to its simplicity and usage in truncal procedures. Objective: This study aims to compare the ultrasound guided bilateral ESP block versus bilateral TAP block on postoperative analgesia after open total abdominal hysterectomy. Study Design: A prospective double-blinded randomized controlled clinical trial. Setting: Zagazig University Hospitals. Methods: After ending of surgical procedure and before reversing of the muscle relaxant, 48 adult female were randomly allocated into two equal groups: group (ES) received bilateral ultrasound guided (ESP) block with 20 ml of bupivacaine 0.375% plus 5ug/ml adrenaline (1:200000) in each side at the level of T9 and group (TA): received bilateral ultrasound guided (TAP) block with the same volume of bupivacaine plus adrenaline. Results: VAS scores at 30 min, 2h, 4h, 6h, 8h, 12h, 16h, 20h and 24h were statistically significant lower in ES group compared to TA group. The time for requirement of first morphine was highly statistically significant prolonged in ES group (14.81±3.52) h compared to TA group (10.58±2.35) h. The total amount of morphine consumption in 24h postoperative was statistically significant decrease in ES group p value=0.01. Incidence of postoperative nausea and vomiting was higher but statistically insignificant in TA group than ES group. There were statistically significant numbers of unsatisfied patients (4) in TA group compared to ES group (no patient). Limitations: Sensorial evaluation of patients was not performed because both blocks have been done under general anesthesia but did not affect outcome. So we recommended further studies comparing between both blocks. Conclusions: Bilateral ultrasound guided erector spinae plane block provides more potent and longer postoperative analgesia with less morphine consumption than transversus abdominis plane block after open total abdominal hysterectomy.