This review focuses on the clinical use of 18F-FDG PET in esophageal cancer. For initial staging of esophageal cancer, 18F-FDG PET is better than chest CT and is complementary to endoscopic ultrasound. Due to its good results for detecting distant metastasis, 18F-FDG PET evades unnecessary curative surgery. Also, PET findings are associated with prognosis in esophageal cancer. 18F-FDG PET seems to be useful for detecting recurrence and restaging in esophageal cancer. For therapy response assessment, 18F-FDG PET is effective after chemotherapy or radiation therapy. 18F-FDG PET is useful to predict pathological response after neoadjuvant therapy in esophageal cancer, which is better than chest CT and endoscopic ultrasound. For radiation therapy planning, 18F-FDG PET may be helpful, but requires further investigations. (Nucl Med Mol Imaging 2008;42(suppl 1):32-38)