Background: We previously reported that positron emission tomography (PET) with 18-F-fluorodeoxyglucose (FDG) might be a useful tool for evaluating the stage of esophageal squamous cell carcinoma (SCC), and that FDG-PET shows greater accuracy in the diagnosis of lymph node metastasis than computed tomography. Further, we elucidated the relationships among FDG-PET performance, glucose transporter (Glut)-1 expression and serum levels of the tumor markers carcinoembryonic antigen (CEA), cytokeratin 19 fragment (CYFRA) and squamous cell carcinoma antigen (SCC-Ag) in esophageal SCC. Patients and Methods: We studied 44 patients with thoracic esophageal SCC who had undergone radical esophagectomy. Immunohistochemical analysis was used to detect the expression of Glut-1 in resected specimens and FDG accumulation was assessed by FDG-PET scan. Results: FDG uptake in the primary tumor was found in 34 out of 44 (77.3%) patients. No significant correlation was observed between SUVs and the tumor markers CEA, CYFRA and SCC-Ag. The survival rate in patients with high FDG uptake (SUV>3) was significantly lower than in cases with low FDG uptake (SUV<3) (p<0.01). A significant correlation was observed between SUV and Glut-1 expression (p < 0.05). The prognosis in patients with both low Glut-1 expression and low FDG uptake tended to be more favorable than in patients with high Glut-1 expression and/or high FDG uptake. Conclusion: Glut-1 expression Was related to FDG uptake, and assessment of both FDG uptake and Glut-1 expression might be useful for providing prognostic information in patients with esophageal SCC.