Sixty patients undergoing shoulder arthroscopy were randomized to receive either an ultrasound-guided erector spinae block (ESPB) with bupivacaine and dexmedetomidine (ESPB + DEX; n=30) or ESPB with bupivacaine alone (ESPB; n=30). The primary outcome of interest was morphine consumption. Secondary outcomes that were assessed were postoperative pain scores, time to first request for rescue analgesia, and adverse events. Morphine consumption was significantly lower in the ESPB + DEX group compared to ESPB alone. Time to first rescue, the number of cases requiring postoperative morphine, and total morphine consumption were all significantly lower in the ESPB + DEX group. Pain scores were significantly lower in the ESPB + DEX group at 12 and 18 hours post-operation.