The prognostic value of the right upper mediastinal lymph node dissection (RUMLND) for patients with middle or lower thoracic esophageal squamous cell carcinoma (ESCC-MLT) is still not well established yet. Our objective is to evaluate the prognostic role of the Sweet procedure plus right upper mediastinal lymph node dissection (MS) by comparing with the Sweet procedure with standard lymph node dissection (SS) in terms of long-term survival. Totally 1,477 ESCC-MLT patients underwent radical intent surgery (186 with MS, 1,291 with SS) at our department between January 2007 and September 2013. After propensity score matching (PSM), 186 patients from each group were matched and analyzed. The 5-year survival rates in two groups were compared by detailed stratifications in terms of clinical characteristics. As for the prognostic role of RUMLND, patients treated with MS tended to obtain higher 5-year survival rate than patients treated with SS in univariate analysis (48.1% vs. 37.4%). Moreover, in multivariate analysis, MS yielded significant higher 5-year survival rate compared with SS (P=0.041). In addition, subgroup analyses of the survival between the MS and SS patients by detailed stratifications demonstrated the survival superiority in the MS group with age <60 years old, TNM stage III, number of lymph node dissection (LND) ≥15, as well as no using of postoperative adjuvant treatment. The RUMLND in Sweet procedure is an independent prognostic factor for ESCC-MLT patients, especially for those with thoracic middle segment-located tumor, stage III or younger.