Cancers of the esophagus and stomach have a major impact on patients' nutritional status by virtue of these organs' inherent digestive functions. Many patients with these cancers will require surgical intervention, which imposes further metabolic demands and compounds preexisting nutritional disorders. Patients with esophagogastric cancer are likely to have lost weight by the time the diagnosis is made. This fact alone is of clinical importance, because it is well known that patients who have lost weight will have higher operative mortality and morbidity rates than patients who maintain their weight. Initial assessment of patients with esophagogastric cancer should include a routine evaluation of nutritional status. This will allow the identification of patients who are at risk of complications, particularly in the postoperative setting. These patients should be targeted for specific nutritional support.