Stomach cancer is still one of the most prevalent malignancies and is the main cause of cancer deaths worldwide. The outcome for patients with metastasis, as well as for those with tumor recurrence, is dismal, with median survival time not greater than a year. Patients with unresectable locally advanced or metastatic lesions have been treated with systemic chemotherapy, and several randomized studies have demonstrated the benefit of chemotherapy compared with best supportive care. Recently, randomized phase III trials have presented a benefit of second-line chemotherapy compared with supportive care alone. However, it is not known at present which drug is the most effective in this setting. In Korea, the practice of offering second-line treatment to patients with advanced gastric cancer (AGC) is common, and many prospective clinical trials investigating clinical outcomes of second-line chemotherapy have been reported. Therefore, to define the potential role of second-line chemotherapy and to help to select an effective regimen, we review the published Korean prospective data concerning the use of chemotherapy in the second-line setting for the treatment of AGC. No phase III trials but 20 phase II trials were identified. The benefit of second-line chemotherapy in AGC has indirect evidence considering prolongation of progression-free survival (PFS) and improvement of the response rate. Taxanes, irinotecan, and oxaliplatin have been studied much and might be promising drugs considering cross-resistance to a 5-fluorouracil and cisplatin combination (FP). A large, prospective, multicenter, randomized phase III study is warranted to select the most effective second-line chemotherapeutic agents.