Background: It has been suggested that nutritional indicators predict the prognosis of esophageal cancer. Nutritional risk (NR) as prognostic factor evaluated by NR index (NRI) in metastatic esophageal squamous cell cancer (ESCC) has not been clarified. Methods: We retrospectively reviewed the data of consecutive patients (pts) with metastatic ESCC who received chemotherapy (CTx) as initial treatment at Shizuoka Cancer Center between April 2008 and December 2015. The selection criteria were as follows: histologically confirmed squamous cell carcinoma; no indication for curative resection or definitive chemoradiotherapy (dCRT); adequate organ function; no prior CTx, radiotherapy (RT) or chemoradiotherapy; no other advanced malignancies. NR was calculated by following formula: NRI = (1.489*serum albumin) + (41.7*present body weight [BW] / ideal BW). NR was classified into 4 groups according to NRI: major (NRI < 83.5), moderate (NRI = 83.5-97.5), mild (NRI = 97.5-100), none (NRI > 100). Multivariate analysis was carried out using cox proportional hazard to estimate the hazard ratio for overall survival (OS). Results: The patients’ characteristics of 138 pts who met the selection criteria were as follows: median age (range), 67 (33-86) years; male/female, 123/15; performance status (PS) 0/1/2, 62/68/8; number of metastatic sites 1/2/3/4, 55/56/23/4; smoking history -/+, 19/119; previous esophagectomy -/+, 118/20; median skeletal muscle index (range), 44.5 (27.8-63.2); median body mass index (range), 20.3 (14.3-27.4); NR major/moderate/mild/none 22/37/26/53; median serum C-reactive protein (CRP) level (range), 0.75 (0.01-20.48) mg/dL. The most common chemotherapy regimen used was fluoropyrimidine plus cisplatin (93%), and 70 patients (50%) received concomitant RT. Median OS was 4.6 months in pts with major NR and 11.8 months in others (p < 0.001). Multivariate analysis for OS identified PS 2, female sex, metastatic sites > 2, CRP ≥ 1mg/dL, and major NR independently associated with poor survival. Conclusions: Major NR calculated by NRI formula associated with poor survival in pts with metastatic ESCC.