BACKGROUND: There is unclear evidence regarding the optimal surgical approach for multilevel cervical spondylotic myelopathy (CSM). The objective of this study was to compare complications, outcomes, and narcotic use in anterior discectomy and fusion (ACDF) vs posterior decompression and fusion (PCDF) in CSM patients. STUDY DESIGN: Registry-based retrospective cohort analysis. METHODS: Patients undergoing 3-level ACDF or PCDF for CSM between 2007 and 2017 were identified from the Humana Claims Database using relevant procedure codes. Propensity score-matched groups were compared in regards to complications, outcomes, and narcotic use. RESULTS: Propensity score matching generated equal cohorts of 6124 patients. The posterior fusion group had a higher rate of urinary tract infection (OR 2.47, < 0.0001), deep vein thrombosis (OR 1.90, < 0.0001), and pulmonary embolism (OR 1.75, < 0.0001). In regards to 30-day outcomes, the posterior approach demonstrated higher rates of stroke (OR 1.68, < 0.0001), wound dehiscence (OR 5.59, < 0.0001), Surgical site infection (SSI) (OR 4.76, < 0.0001), wound revision surgery (OR 3.02, < 0.0001), and all-cause readmission (OR 2.01, < 0.0001). One-year outcomes revealed higher rates of pseudarthrosis (4.7% vs 2.0%, OR 2.43, < 0.0001) and revision or extension surgery (OR 2.33, < 0.0001) in the posterior fusion cohort. These patients also demonstrated significantly higher mean morphine milligram equivalent used at 30 days (OR 1.19, < 0.0001), as well as 60 (OR 1.20, < 0.0001), 90 (OR 1.21, < 0.0001), and 120 (OR 1.21, < 0.0001) days. CONCLUSIONS: This nationwide propensity-matched analysis of multilevel CSM patients found the posterior approach to be associated with increased rates of inpatient complications, wound complications, 30-day readmission, 1-year pseudarthrosis, and 1-year revision or extension surgery. These patients also demonstrated higher levels of narcotic use up to 120 days after surgery. CLINICAL RELEVANCE: The posterior approach for treatment of CSM may be associated with increased rates of short- and long-term complications in addition to increased narcotic consumption in comparison to the anterior approach.