Background: Myofascial plane block has recently replaced central neuraxial analgesia as the preferred method of effective, opioid-sparing pain treatment. The use of external oblique intercostal (EOI) nerve blocks to treat postoperative pain has increased recently because they can relieve pain in the upper midline and upper lateral abdominal wall. Objectives: To evaluate the effect of external oblique intercostal plane block (EOIPB) on the postoperative pain that was evaluated by visual analogue pain scale (VAS) as a primary objective. Time to first rescue analgesia, 24 hours' postoperative consumption of analgesia, perioperative hemodynamics, postoperative anesthetic care unit (PACU) stay, patient satisfaction, and postoperative complications were the secondary objectives. Patients and Methods: This prospective and randomized controlled study was conducted on fifty patients with ASA I and II, aged ≥ 20 to ≤ 70 years, scheduled for upper abdominal surgeries. Patients were divided equally into two groups, group (A) Patients received US-guided EOIB with 20 ml of 0.25% bupivacaine on each side after induction, and group (B) Patients received postoperative morphine on patient request. Results: The EOIPB group showed a significantly lower VASscore than the control group at 0 time, 1h, 2h, 4h, 8h and 12h postoperatively (p < 0.001), but there was no significant difference at postoperative 24h between the two groups (p>0.05). Postoperative 24-hour morphine consumption was significantly lower in the EOIPB group than in the control group (9.8±2.4 (6-15) mg vs. 19.4±2.7 (15-25) mg respectively, P<0.001). Similarly, the time until the first required analgesia was significantly longer in EOIPB group (8.1 ±0.8(7-9) vs. 4.1 ±0.8(3-5) in hours, respectively, P<0.001). Conclusion: We concluded that EOIPB resulted in decreased postoperative pain, morphine, and fentanyl usage while increasing patient satisfaction.