AIM: To evaluate whether preoperative mean corpuscular volume (MCV) is a prognostic indicator in patients with resectable esophageal squamous cell carcinoma (ESCC). METHODS: A total of 298 consecutive, prospectively enrolled patients with histologically diagnosed ESCC who underwent surgery with curative intent from 2001 to 2011 were retrospectively evaluated. Patients were excluded if they had previous malignant disease, distant metastasis at the time of primary treatment, a history of neoadjuvant treatment, had undergone nonradical resection, or had died of a non-tumor-associated cause. Survival status was verified in September 2011. Pathological staging was performed based on the 2010 American Joint Committee on Cancer criteria. Preoperative MCV was obtained from blood counts performed routinely within 7 d prior to surgery. Receiver operating characteristic (ROC) curve analysis was used to determine a cutoff for preoperative MCV. RESULTS: The 298 patients consisted of 230 males and 68 females, with a median follow-up of 30.1 mo. ROC analysis showed an optimal cutoff for preoperative MCV of 95.6 fl. Fifty-nine patients (19.8%) had high (> 95.6 fl) and 239 (80.2%) had low (≤ 95.6 fl) preoperative MCV. Preoperative MCV was significantly associated with gender (P=0.003), body mass index (P=0.017), and preoperative red blood cell count (P<0.001). The predicted 1-, 3and 5-year overall survival (OS) rates were 72%, 60% and 52%, respectively. Median OS was significantly longer in patients with low than with high preoperative MCV (27.5 mo vs 19.4 mo, P<0.001). Multivariate analysis showed that advanced pT (P=0.018) and pN (P<0.001) stages, upper thoracic location (P=0.010), lower preoperative albumin concentration (P=0.002), and high preoperative MCV (P=0.001) were negative prognostic factors in patients with ESCC. Preoperative MCV also stratified OS in patients with T3, N1-N3, G2-G3 and stage Ⅲ tumors. CONCLUSION: Preoperative MCV is a prognostic factor in patients with ESCC. AIM: To evaluate whether preoperative mean corpuscular volume (MCV) is a prognostic indicator in patients with resectable esophageal squamous cell carcinoma (ESCC). METHODS: A total of 298 consecutive, prospectively enrolled patients with histologically diagnosed ESCC who underwent surgery with curative intent from Patients were excluded if they had previous malignant disease, distant metastasis at the time of primary treatment, a history of neoadjuvant treatment, had undergone nonradical resection, or had died of a non-tumor-associated cause. Survival status was verified in September 2011. Pathological staging was performed based on the 2010 American Joint Committee on Cancer criteria. Preoperative MCV was obtained from blood counts performed routinely within 7 d prior to surgery. Receiver operating characteristic (ROC) curve analysis was used to determine a cutoff for preoperative MCV. RESULTS: The 298 patients consisted of 230 males and 6 ROC analysis showed an optimal cutoff for preoperative MCV of 95.6 fl. Fifty-nine patients (19.8%) had high (> 95.6 fl) and 239 (80.2%) had low ( ≤ 95.6 fl) preoperative MCV. Preoperative MCV was significantly associated with gender (P = 0.003), body mass index (P = 0.017), and preoperative red blood cell count Overall survival (OS) rates were 72%, 60% and 52%, respectively. Median OS was significantly longer in patients with low than high preoperative MCV (27.5 mo vs 19.4 mo, P <0.001). Multivariate analysis showed that advanced pT (P = 0.001), and high preoperative MCV (P = 0.001) were negative prognostic factors in patients with ESCC (P = 0.001) . Preoperative MCV also stratified OS in patients with T3, N1-N3, G2-G3 and stage III tumors. CONCLUSION: Preoperative MCV is a prognostic factor in patients wi th ESCC.