In esophageal squamous cell carcinoma (ESCC), extracapsular extention (ECE) in metastatic lymph nodes portends high rate of recurrence and poor prognosis. To our knowledge, the effectiveness of postoperative chemoradiotherapy (CRT) in these patients has never been investigated. In this retrospective study, we compared the outcomes of surgery with or without postoperative chemoradiotherapy in ESCC patients with ECE. Based on log-rank stratified by T stage, postoperative adjuvant CRT significantly improved the overall survival (p=0.017) and progression free survival (p=0.002). In multivariate analysis, adjuvant CRT was identified as an independent prognostic factor (HR=0.494, CI 0.290-0.844, p=0.010). Compared with surgery alone, the CRT group had significantly fewer cases of regional recurrence (P=0.048) and overall recurrence (P=0.024). However, there was no significant difference in distant metastasis between two groups (P=0.755). In conclusion, our data suggest that the postoperative adjuvant CRT might be beneficial in selected subgroups of ESCC patients with ECE. To further verify these results, a prospective trial with a large sample size is needed.