Study Design: Retrospective study. Objective: To determine the presence of any potential associations between anesthesia time with postoperative outcome and complications following elective anterior cervical discectomy and fusion (ACDF). Methods: Patients who underwent elective ACDF were identified in the American College of Surgeons National Quality Improvement Program database. Patient demographics, medical comorbidities, and perioperative and postoperative complications up to 30 days were analyzed by univariate and multivariate analysis. Results: A total of 3801 patients undergoing elective ACDF were identified. Patients were subdivided into quintiles of anesthesia time: Group 1, 48 to 129 minutes (n = 761, 20%); Group 2, 129 to 156 minutes (n = 760, 20%); Group 3, 156 to 190 minutes (n = 760, 20%); Group 4, 190 to 245 minutes (n = 760, 20%); and Group 5, 245 to 1025 minutes (n = 760, 20%). Univariate analysis showed significantly higher rates of any complication (P <.0001), pulmonary complication (P <.0001), intra-/postoperative blood transfusions (P <.0001), sepsis (P =.017), wound complications (P =.002), total length of stay >5 days (P <.0001), and return to operating room (P =.006) in the highest quintile compared to those of other groups. Multivariate regression analysis revealed that prolonged anesthesia was an independent factor for increased odds of overall complications (odds ratio [OR] = 2.71, P =.012), venous thromboembolism (OR = 2.69, P =.011), and return to the operating room (OR = 2.92, P =.004). The 2 groups with the longest anesthesia durations (quintiles 4 and 5) had increased total length of stay more than 5 days (for quintile 4, OR = 3.10, P =.0004; for quintile 5, OR = 3.61, P <.0001). Conclusion: Prolonged anesthesia duration is associated with increased odds of complication, venous thromboembolism, increased length of stay, and return to the operating room.