Although sentinel node (SN) biopsy has been utilized to predict regional lymph node metastasis in patients with melanoma and breast cancer, the validity of the SN hypothesis is still controversial in regard to esophageal cancer. SN mapping for esophageal cancer is relatively complicated compared to that for gastric cancer, and the number of early-stage esophageal cancers is limited. Therefore, only a few studies have demonstrated the feasibility and validity of the SN concept for esophageal cancer. Nevertheless, our preliminary studies showed that SN mapping may be feasible in patients with early-stage esophageal cancer. Transthoracic extended esophagectomy with three-field radical lymph node dissection has been recognized as a curative procedure for thoracic esophageal cancer in Japan. However, uniform application of this highly invasive procedure might increase the morbidity and markedly reduce quality of life (QOL) after surgery. Although further accumulation of evidence based on multicenter clinical trials using standard protocol is required, SN mapping would provide significant information on individualized selective lymphadenectomy, which might reduce the morbidity and retain the patients' QOL.