Cancers of esophagus and stomach are common malignant diseases worldwide, and they are associated with serious morbidity and high mortality rates. When diagnosed at an early stage, gastro-esophageal cancers are potentially curable. Neo-adjuvant or adjuvant therapies using both chemotherapy and radiation therapy have been shown to reduce the risk of local recurrence and distant metastasis. For advanced or metastatic tumors, systemic chemotherapy offers symptomatic palliation and moderate benefits in survival. With recent advances in anti-cancer therapeutics, progress has been made to improve treatment response and life expectancy in patients with advanced gastro-esophageal cancers. Furthermore, the clinical use of molecularly targeted agents in combination with cytotoxic chemotherapeutics is being evaluated in a number of ongoing clinical trials. In this article, we review currently used standard systemic therapies including recently evolving targeted therapies for metastatic gastro-esophageal cancers, as well as the proven role and the regimens that are used as neoadjuvant and adjuvant treatment in localized gastro-esophageal cancers.