Background.The postmastectomy pain syndrome (PMPS) is chronic pain after breast cancer surgery and is reported to influence quality of life. The aim of this study was to provide long term reduction of PMPS, improve range of motion of the shoulder, and decrease the need for postoperative analgesia using ultrasound guided stellate ganglion block.Method.Sixty patients with PMPS were randomly allocated into 1 of 3 groups: bupivacaine group (group 1), bupivacaine plus ketamine group (group 2), and bupivacaine plus morphine group (group 3). Each patient received 3 blocks with an interval of one week in between. Patients were assessed for: pain visual analogue score (VAS), movement of the shoulder, skin temperature, and the need for analgesic drugs.Results.The pain VAS was significantly decreased in group 2 as compared to the other two groups. Shoulder movement improved significantly in the three studied groups with the best results observed after the third block. The need for the analgesic drugs in the form of gabapentin was more in the bupivacaine and bupivacaine plus morphine groups than in bupivacaine plus ketamine group.Conclusion.Treatment of PMPS with ultrasound guided stellate ganglion block using ketamine (0.5 mg/kg) as adjuvant to bupivacaine (0.25%) successfully decreased pain VAS and the need for analgesic drugs.