Non-small cell lung cancer is a frequent type of cancer, with approximately 1.2 million cases per year expected worldwide. A total of 20-30% of patients with early stage non-small cell lung cancer are amenable to radical surgery, although only 40-50% of these patients are cured. An improvement in survival has never been demonstrated for postoperative radiotherapy. However, a major step forward is several recent large randomized studies that have demonstrated improved survival with postoperative chemotherapy. This review covers the historic data on adjuvant chemotherapy for non-small cell lung cancer, meta-analyses, modern studies with cisplatin-based or other chemotherapy, implications for current clinical practice and guidelines, some practical recommendations and, finally, the questions for future studies.