The sentinel node (SN) is defined as the first draining node from the primary lesion, and it has proven to be a good indicator of the metastatic status of regional lymph nodes in solid tumors. Recently, the validity of the SN concept in gastric cancer has been demonstrated by a number of single institutional studies, and prospective multi-center trials are presently ongoing. The Gastric Cancer Surgical Study Group of the Japan Clinical Oncology Group (JCOG) organized a multi-center prospective study of SN mapping by the dye-guided method using subserosal injection of indocyanine green. If the JCOG study reveals favorable results, in terms of false-negative rates, the dye-guided method will be utilized as a routine practice for open surgery in a wide range of institutions. If not, we will need to consider introduction of radioguided method or add further technical improvements, even for open surgery. A study group in the Japan Society of Sentinel Node Navigation Surgery is also conducting a multi-center prospective trial of SN mapping by a dual tracer method with blue dye and radio-active colloid. Even if the SNNS study demonstrates acceptable detection rates and low false-negative rates, we need to conduct a feasibility study of laparoscopic SN mapping for gastric cancer as the next step. The results of these clinical trials should provide useful perspectives on the future direction of SN navigation surgery for gastric cancer.