Purpose: To retrospectively report on a series of patients who had interscalene block regional anesthesia performed for outpatient open and arthroscopic shoulder surgical procedures in a community-based ambulatory surgery center setting. Methods: We reviewed the cases of 1,945 patients who had interscalene block regional anesthesia performed during an 8-year period. Results: The complication rate was 0.63%, with all complications occurring in the immediate postoperative period, none of which were permanent. Conclusions: With an expert, experienced anesthesia team, the interscalene block can be a safe method (temporary complication rate, 0.63%) of intraoperative anesthesia and perioperative analgesia for outpatient open and arthroscopic shoulder surgery in physician-owned ambulatory surgery centers. Level of Evidence: Level IV, therapeutic case series.