Surgery is the main curative treatment of patients with non-small cell lung cancer (NSCLC), but half of all patients will experience local or distant failure after complete resection. An individual data-based meta-analysis has suggested a 13% reduction in the risk of death and an absolute benefit of 5% at 5 years with adjuvant cisplatin-containing chemotherapy in patients with resected NSCLC. These data led several national and international groups to initiate a new generation of adjuvant trials in resected NSCLC, and more than 2,500 patients have already been included in these randomized studies. Chemotherapy can also be proposed preoperatively. Two randomized studies, which included 60 patients each, strongly suggested a benefit from neoadjuvant chemotherapy in patients with stage III NSCLC. A large French randomized study that included 375 patients with early stage NSCLC who did or did not receive preoperative chemotherapy has recently been completed. This study should help clarify the role of neoadjuvant chemotherapy in operable NSCLC.