Background: Postoperative complications after esophagectomy can lead to considerable patient discomfort and prolonged length of hospital stay. Lack of physical activity can be one of the independent risk factors for postoperative complications because physical activity is closely related to physical function. The objective of this study was to determine whether physical activity among esophageal cancer patients decreases their risk of postoperative complications after esophagectomy. Materials and Methods: We investigated 51 consecutive patients with newly diagnosed resectable esophageal cancer who were scheduled to receive esophagectomy between January 2009 and November 2011. Demographic, clinicopathologic, and treatment information were recorded and physical function was measured. The last 7-days short version of the International Physical Activity Questionnaire was used to assess physical activity before the operation. Stepwise multiple logistic regression analysis was used to determine whether preoperative physical activity is related to the risk of postoperative complications. Results: Male gender [OR 18.6, (95%CIs: 1.2-284.4); P=0.035], 3-field lymph node dissection (OR 9.6, [95%CIs: 1.4-66.6]; P=0.022), low-level physical activity (OR 28.3, [95%CIs: 3.5-227.7]; P=0.002), and preoperative comorbidities [OR 5.9, (95%CIs: 1.1-31.5); P=0.037] were found to be independently associated with postoperative complications. Conclusions: The present study shows that low-level physical activity, preoperative comorbidities, and 3-field lymph node dissection are independent and significant risk factors for postoperative complications after esophagectomy. Although further study is required, maintaining high-level physical activity preoperatively may decrease the risk of postoperative complications.