Importance: Significant cost savings can be achieved from consolidating purchases of spinal implants with a single vendor. However, it is currently unknown whether sole-source contracting or vendor rationalization more broadly affects patient care., Objectives: To describe the single-vendor procurement of spinal implants, characterize the economic benefits of sole-source contracting, and gauge whether vendor rationalization is associated with a diminished quality of care., Design, Setting, and Participants: This retrospective cohort study assessed adult patients receiving single-level lumbar interbody fusions at a single institution from January 1, 2009, to July 31, 2017. Exclusion criteria included multilevel fusions and prior spinal fusions., Exposures: Patients were analyzed based on the number of vendors available to surgeons at the time of the patient's surgery. January 1, 2009, to December 31, 2010, was defined as the multivendor period (10 vendors); January 1, 2011, to December 31, 2014, was defined as the dual-vendor period; and January 1, 2015, to July 31, 2017, was defined as the single-vendor period., Main Outcomes and Measures: Rates of 12-month revision surgery, complications, 30-day readmissions, and postoperative patient-reported outcomes, as measured by 5-dimension European Quality of Life (EQ-5D) and Patient-Reported Outcomes Measurement Information System-Global Health (PROMIS-GH) utilities. Propensity score weighting was performed to control for confounding. The Holm method was used to correct for multiple testing. Annual cost savings associated with the dual-vendor and single-vendor periods were also reported., Results: A total of 1373 patients (mean [SD] age, 59.2 [12.6] years; 763 [55.6%] female; 1161 [84.6%] white) were analyzed. Rates of revisions after adjusting for confounding were 3.2% (95% CI, 1.5%-6.7%) for the multivendor period, 4.5% (95% CI, 3.1%-6.5%) for the dual-vendor period, and 3.0% (95% CI, 1.7%-5.0%) for the single-vendor period. Complication rates were 5.3% (95% CI, 2.7%-10.1%) for the multivendor period, 7.2% (95% CI, 5.4%-9.6%) for the dual-vendor period, and 6.4% (95% CI, 4.6%-8.8%) for the single-vendor period. Readmission rates were 14.2% (95% CI, 9.7%-20.2%) for the multivendor period, 12.6% (95% CI, 10.1%-15.5%) for the dual-vendor period, and 9.7% (95% CI, 7.4%-12.7%) for the single-vendor period. Revisions, complications, and patient-reported outcomes were statistically equivalent across all periods. Readmissions were not statistically equivalent but not statistically different. The savings attributable to vendor rationalization were 24% for the dual-vendor and 21% for the single-vendor periods., Conclusions and Relevance: The single-vendor procurement of spinal implants was associated with significant cost savings without evidence of an associated decline in the quality of care. Large hospital systems may consider sole-source purchasing as a viable cost reduction strategy.