Objectives To evaluate the effect of preoperative body mass index (BMI) on the perioperative and long-term results in esophageal squamous cell cancer patients. Method We retrospectively analyzed the clinical data of 503 patients with esophageal cancer between January 2001 and December 2009. There were 268 males and 235 females with the median age of 57 years ranging from 32-88 years. The associations between preoperative BMI and clinic patholo-gical characteristics were assessed by using the χ2 or Fisher's exact test. Survival analysis was performed by Kaplan-Meier curves with log-rank tests. ResultsThe 1-year, 3-year, 5-year, and 10-year overall survival rate for the entire cohort of patients was 64.0%, 49.0%, 43.0%, and 41.0% respectively. The occurance rates of weight loss, lymph node metastases, and poorly differentiated tumorigenesis represented statistically higher in patients with BMI≤18.5 kg/m2 than those in the patients with BMI>18.5 kg/m2 (P=0.026, P=0.006, P=0.048). For the cohort, the Kaplan-Meier survival analysis showed a significant trend toward a decreased survival in esophageal cancer patients with underweight (P=0.001). No statistical difference in overall complication, anastomotic leakage, and pulmonary complication rate was detected among the different BMI classes(P=0.162, P=0.590, P=0.376). Univariate and multivariate analysis showed that the drinking status, pathological stage, and underweight were the independent prognostic factors. ConclusionsAfter esophagectomy, BMI is not associated with the incidence of postoperative complications in patients. Patients with underweight are usually diagnosed with advanced stage, therefore tend to have poorer survivals than those with normal or over-weight.