Background: Though neoadjuvant chemotherapy with docetaxel/cisplatin/5-fluorouracil (DCF) showed a promising efficacy in patients (pts) with resectable esophageal squamous cell carcinoma (ESCC), grade 3 anorexia during the course and body weight loss (BWL) were frequently experienced. BWL is considered as a factor for poor survival in operable cancer pts, however, there is rarely reported of the relationship of BWL during neoadjuvant therapy and survival. Methods: We retrospectively evaluated pts of ESCC withclinical stage II or III, excluding T4, who had received neoadjuvant DCF and esophagectomy (R0 resection) at our institution between April 2010 and December 2018. We define the cut-off level at more than 3% weight reduction (BWL3 group) between before and after of first cycle of DCF. Results: Among the 77 pts who were selected for this analysis, 13 patients showed BWL > 3% (BWLS group), and other 64 pts did not (no-BWL group). The median age, proportions of performance status of 0, cT3 stage, cN2-3 stage and serum albumin lower than normal level in no-BWL and BWL3 group were 65 and 67y.o, 59 and 77%, 88 and 54%, 75 and 69%, 34 and 31%, respectively. There was no significant difference inhistological therapeutic effect (grade 2-3) with 50% in no-BWL and 62% in BWL3 group (P = 0. 549). The incidence of postoperative grade 2 or higher pneumoniawas same in both group (23% vs 17%, P = 0. 695). The median overall survival (OS) was not reached in non-BWL group and 39.5 m in BWL3 group (P = 0.048), respectively. The median progression free survival (PFS) was not reached in non-BWL group and 39.5 m in BWL3 group (P = 0.382), respectively. In multivariate analysis, BWL is independent prognostic factor for OS (hazard ratio [HR] = 11.5, 95%CI: 2.45-53.8, P = 0.002). Conclusions: Our exploratory study demonstrated that body weight loss during first course of neoadjuvant DCF therapy for ESCC patients may be a prognostic factor for survival.