Open nephrectomy is associated with substantial postoperative pain. Epidural analgesia is a very useful option but with many risks. Systemic analgesics in the form of opioid analgesics may give rise to side effects like nausea , vomiting , constipation , allergy or drowsiness. Erector spinae plane (ESP) block is one of the interfascial plane blocks that target the dorsal and ventral rami of the spinal nerves. Recent studies demonstrated effective postoperative analgesia for ESPB after thoracic and abdominal surgeries. Paravertebral block (PVB) is a technique where a local anesthetic is deposited into a space found on both sides of the spine. Some studies showed that PVB is effective for pain relief in the thoracic and abdominal surgeries. Aim: to evaluate the analgesic effect of US-guided ESP block and thoracic paravertebral block in patients undergoing elective open nephrectomy surgery. Methods: forty five patients aged from 30-60 years scheduled for elective open nephrectomy surgeries under general anesthesia and classified to one of three groups (ESPB group , PVB group and Control group). Postoperative pain was assessed by the visual analogue score at 2, 4, 6, 12, 18, and 24 hours postoperatively and the total 24-hours morphine consumption was recorded. Results: We reported that both ESP block and PVB significantly reduced total morphine consumption and the VAS score at 24 hours postoperatively compared to the control group. Total morphine consumption 24 h postoperatively was decreased to about 60% (morphine sparing about 40%) with both ESP block and PVB compared to the control group. we also reported that there was no statistical significance between the PVB group and the ESPB group according to total morphine consumption and the VAS scores in 24 hours postoperatively. Conclusion: Both ESP and PVB block provided better postoperative analgesia compared to IV morphine after open nephrectomy surgeries. Physicians could perform either PVB or ESB according to their clinical experiences and personal choices.