Background: Different adjuvants have been used with local anesthetics to improve quality of regional anesthesia (sub-arachnoid, epidural or combined sub-arachnoid and epidural block) and to avoid intra-operative visceral and somatic pain and to provide prolonged post-operative analgesia. Dexmedetomidine is a highly selective α₂-adrenergic agonist which has both analgesic and sedative properties when used as an adjuvant in regional anesthesia. Objective: Evaluation of the effect of intrathecal hyperbaric bupivacaine plus dexmedetomidine on the onset and duration of sensory and motor block, intra-operative hemodynamic stability (changes), surgeon's satisfaction, intraoperative adverse effects and postoperative analgesia. Patients and method: Sixty females in childbearing period (22-40 years old), ASA physical status I scheduled for elective cesarean section. Patients were randomly allocated to receive intrathecal either 12.5 mg of (0.5%) heavy bupivacaine [B control group], or 7.5mg of (0.5%) heavy bupivacaine plus 8 ug dexmedetomidine [BD study group].  Results: Patients in BD group had a significantly rapid onset and longer duration of sensory and motor block than control B group. Onset of postoperative pain significantly delayed in BD group. Moreover, abdominal muscle relaxation was excellent clinically, with marked reduction in side effects as nausea, vomiting, hypotension and bradycardia compared with control B group. No side effects were recorded on babies as regard the neonatal assessment in both groups. Conclusion: The low dose of intrathecal anesthetic agent (Bupivacaine 7.5 mg) with 8 ug  Dexmedetomidine had a significantly rapid onset and associated with prolonged motor and sensory block, hemodynamic stability and decreased postoperative analgesic consumption compared with (Bupivacaine 12.5 mg) alone.