Background: Inadequate postoperative pain relief can delay recovery, increase healthcare costs and reduce patient satisfaction. Some studies revealed that spinal bupivacaine-dexamethasone had almost the same analgesic potency as bupivacaine-fentanyl with opioid-sparing and antiemetic effects. The optimumdose of spinal dexamethasone for postoperative analgesia has not been yet evaluated. So, it became mandatory to conduct a study clearing the safety and the optimum dose of spinal dexamethasone for postoperative analgesia in patients undergoing abdominal hysterectomy. Aim: Optimizing post-operative analgesia using two different doses of intrathecal dexamethasone added to bupivacaine in patients undergoing abdominal hysterectomy. Patients and methods: This study was conducted atDepartment of Anaesthesia, Intensive Care and Pain Management, Zagazig University Hospitals on patients who were undergo elective abdominal hysterectomy. The patients were divided into group (C: Control group who were received intrathecal Bupivacaine 0.5% 4cc plus 1cc normal saline, group (D2): who were received intrathecal Bupivacaine 0.5% 4cc plus 2 mg dexamethasone in 1cc volume and group (D4) n= 43: who were received intrathecal Bupivacaine 0.5% 4cc plus 4mg dexamethasone in 1cc volume. Results:There was statistically significant difference between group C with D4 at different periods of follow up and there was statistically significant difference between group D2 with D4 from period 0 hr. to 12 hr P.O regarding post-operative pain.