The primary endpoint of this study is to investigate the effect of adding nalbuphine to intrathecal morphine on quality of postoperative analgesia and Morphine related side effects post- cesarean delivery.

The study will be performed in Assiut University Hospitals, after obtaining approval from the local ethics committee and written informed patient consent. All patients will have a peripheral IV cannula 18 G inserted; standard non-invasive monitors will be applied. All the patients will be preloaded with 10 ml/kg Ringer's lactate solution intravenous. Intrathecal block under strict aseptic conditions will be performed in sitting position at L3-4 or L4-5 inter-spinous space with 25G pencil-point spinal needle. All patients will receive intrathecal 10 mg of 0.5% hyperbaric bupivacaine.

Inclusion Criteria:

• Female patients
• age between 16 to 40 years
• ASA physical status I - II

Exclusion Criteria:

• Infection at the site of injection.
• Coagulopathy or other bleeding diathesis.
• Preexisting neurologic deficits.
• History of hypersensitivity to any of the given the drugs.
• Inability to communicate with the investigator and the hospital staff.
• History of chronic opioid us