Gastric cancer is the second most common cancer and the third leading cause of cancer-related deaths in Korea. Many cases of gastric cancer are detected in the early stages on standard medical examinations; complete surgical and endoscopic resection is the most recommended treatment for early-stage gastric cancer. Nevertheless, many patients have already progressed to advanced gastric cancer (AGC) upon diagnosis, and the prognosis of such patients is very poor. Combination chemotherapy has been shown to produce a better quality of life (QOL) and to increase overall survival in AGC patients. However, approximately 50% of patients do not respond to the current first-line chemotherapy, while most patients who do respond eventually show disease progression. Accordingly, various second-line regimens have been investigated, and active salvage chemotherapy has been shown to improve the QOL and clinical outcomes in select AGS patients who can tolerate it. There is also an increasing need for neoadjuvant therapy for treating gastric cancer; therefore, various clinical trials have been set up to investigate different regimens. Neoadjuvant therapy is currently established as the standard treatment for locally AGC in Europe; it has contributed to lowering the nodal stages and has reduced overall mortality rates. Despite these benefits, many uncertainties remain. Therefore, further prospective, high quality randomized controlled trials for neoadjuvant therapies are needed to clarify their clinical benefits and to establish the most effective treatment strategies for AGC.