BACKGROUND: We performed a nationwide analysis to assess the impact of adjuvant therapy on survival after a microscopically margin-positive (R1) resection for esophageal cancer. METHODS: The National Cancer Database was used to identify patients with R1 resection for esophageal cancer (2004-2015). Patients were grouped by type of adjuvant therapy. Patients who had other margin status, M1 disease, neoadjuvant chemotherapy and radiation, missing survival, and no or unknown treatment were excluded. The primary outcome was overall survival. A 1:1 propensity score-matched sensitivity analysis was also performed comparing patients who received no adjuvant therapy with those who received adjuvant chemoradiation. RESULTS: Of 546 patients, 279 (51%) received adjuvant therapy and 267 (49%) did not. Patients receiving adjuvant therapy were more likely to be younger, have more advanced pathologic stage, have nonsquamous histology, and have shorter hospitalization. In multivariable analysis, adjuvant chemotherapy, radiation, and chemoradiation were all associated with improved survival compared with no adjuvant therapy. In a propensity score-matched analysis of 123 patient pairs, adjuvant chemoradiation was associated with improved survival compared with no adjuvant therapy (adjusted HR: 0.30; 95% CI: [0.22, 0.40]). CONCLUSIONS: Adjuvant therapy is associated with improved survival compared with no adjuvant therapy in patients with R1 resection for esophageal cancer even after adjustment for pathologic stage. Adjuvant therapy should be considered in patients with incompletely resected esophageal cancer in concordance with national guidelines.