For patients with gastro-esophageal cancer ultrasonography (EUS) is superior to any other imaging modality in the assessment of local tumor infiltration and local lymph nodes status. EUS is especially important in the preoperative staging of patients with esophageal cancer and patients with proximal gastric cancer. Here it allows for the identification of those patients with advanced disease who are unlikely to benefit from surgery and in whom a conservative palliative treatment is indicated. In advanced gastric cancer the clinical implications of EUS less clear. Still preoperative EUS is indicated in every patient with cancer of the proximal stomach to assess tumor infiltration in the esophagus. Relatively new is the use of EUS in staging early cancers in order to select patients for local endoscopic treatment. High-frequency miniprobes are the instruments of choice for imaging these lesions. Strict criteria should be applied in the selection of patients for local endoscopic treatment of early gastro-esophageal cancers. EUS guided fine needle aspiration (EUS-FNA) is currently only indicated in patients with esophageal cancer and suspicious celiac lymph nodes. It may become more important if new treatment protocols demand more objective and reliable assessment of lymph node status.