BACKGROUND CONTEXT Identifying patient characteristics that predict MMI achievement may improve surgical care and patient satisfaction. PURPOSE The purpose of this study is to identify the time point at which patients undergoing primary, single-level anterior cervical discectomy and fusion (ACDF) can be considered to have reached maximal medical improvement (MMI). STUDY DESIGN/SETTING Retrospective. PATIENT SAMPLE 69 patients undergoing ACDF. OUTCOME MEASURES Maximal Medical Improvement, Neck Disability Index. METHODS A surgical database was retrospectively reviewed between 2014-2017 for patients undergoing ACDF for degenerative pathology. Neck Disability Index (NDI) scores were collected preoperatively and at 6-week, 3-month, 6-month, and 12-month follow-up. The minimal clinically important difference (MCID) was calculated using distribution-based methodology at the 1-year interval and validated using a nonparametric receiver operating characteristic (ROC) curve. Area under curve (AUC) analysis was used to validate predictive power. The time period at which patients achieved MCID was determined and plotted using a Kaplan-Meier survivorship curve. MMI was defined as the interval at which 90% of patients achieved MCID. A Cox hazard proportion model was used to determine whether age, body mass index (BMI), and Charlson Comorbidity Index (CCI) were associated with time to achieve MCID. RESULTS A total of 69 patients were included in the analysis. Average NDI scores were 37.9 preoperatively, 30.7 at 6 weeks, 25.1 at 3 months, 21.3 at 6 months, and 22.0 at 12 months postoperatively. The change in NDI reflective of MCID was calculated to be -11.0 (AUC=100%). In total, 51 patients (73.9%) achieved MCID within the study period, with median time to achievement being 3 months. Of these patients, 95.7% achieved MCID by 6 months postoperatively, thus allowing the establishment of MMI at this time point. No association was identified between age (HR: 1.014, p=0.606), BMI (HR: 0.984, p=0.552), or CCI (HR: 0.932, p=0.719), and time to achieve MCID. CONCLUSIONS The majority of patients undergoing ACDF achieved MCID at 3 months follow-up, while over 95% of patients who achieved MCID reached this threshold by 6 months following surgery. As such, future outcome reporting in patients undergoing ACDF should include follow-up to 6 months postoperatively. Providers can also utilize this information to better counsel patients regarding postoperative expectations following ACDF. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.