Background <p>This study evaluated the association between adjuvant chemotherapy and the survival of cT1b-T2 patients with incidentally discovered positive lymph nodes (cN- but pN+) after esophagectomy for esophageal squamous cell carcinoma.</p> Materials and methods <p>Esophageal cancer patients in whom positive lymph nodes were incidentally discovered after esophagectomy were enrolled in this retrospective cohort study. Patients were divided into the surgery alone and adjuvant chemotherapy groups. Propensity score matching (1:1) was used to minimize baseline differences.</p> Results <p>In total, data from 343 patients who were incidentally discovered to have positive lymph nodes after surgery were analyzed. Each group consisted of 107 patients, with no significant difference in the background information between the two groups. There was also no significant difference in the overall survival (<i>P</i> = 0.227) or disease-free survival (<i>P</i> = 0.210) between the groups in the matched overall study population. Notably, in subgroup analysis, The disease-free survival in the adjuvant chemotherapy group was significantly better than that in the operation group alone for patients with pathological stage T3 (<i>P</i> = 0.023). Multivariate analysis showed that male (ref: female, HR = 1.796, 95% CI, 1.013–3.183, <i>P</i> = 0.045) was a significant independent predictive factor for overall survival.</p> Conclusion <p>Adjuvant chemotherapy may improve survival for patients with cT1b-T2 but pathological T3 stage patients with incidentally discovered node-positive esophageal squamous cell carcinoma.</p>