The concept of the sentinel lymphatic node was introduced by Cabanas in 1977, but it has proved to be successful for the treatment of the melanoma and breast cancer only since the 90s. Many studies have recently extended this technique to other neoplasias. This study deals with 36 patients who were to undergo surgery for 14 gastric adenocarcinomas, 11 of the colon and 11 pulmonary. Once the neoplastic mass was detected, 2 to 5 ml of a vital dye (Blu Patent) were injected in the serosa along the perimeter of the tumor by means of several 0.5 ml injections. A lymphatic node was diagnosed in 22 patients, respectively 10 gastric neoplasias, 6 pulmonary, 6 of the colon. In 14 cases the lymphatic node was found to be negative, in 8 cases positive. In the remaining 14 patients the lymphatic node was not detected. Although data do not always agree, the sentinel lymphatic node technique seems to have been successful for this kind of tumors. For this reason we have carried out this study and published our first data.