Esophageal cancer is associated with malnutrition in the vast majority of patients. This phenomenon is partly attributed to the disease process itself, the location of the tumor and other factors, such as dysphagia which is often accentuated due to chemotherapy/ radiotherapy treatment or surgical intervention. The poor nutritional status of these patients is often related to the presence of cancer cachexia, altered metabolism, and tissue wasting. Malnutrition in this patient population affects quality of life, worsens patient's tolerance to chemotherapy and accounts for lower survival. Nutritional management of these patients includes both proper nutritional assessment and support and might prevent, to a certain extent, the manifestation of malnutrition-related consequences. The purpose of this article is to review the current literature in order to focus on the etiology and diagnosis of malnutrition in esophageal cancer patients, emphasizing also on the optimal nutritional support during multimodality treatment.