Despite improved surgical techniques, relapse and mortality rates remain high among patients with resected non-small cell lung cancer. Numerous randomized controlled trials in the 1980s and 1990s were unable to demonstrate a consistent survival benefit for adjuvant chemotherapy. However, in the past 2 years, the results of three pivotal trials have unequivocally shown the benefit to adjuvant treatment in resected non-small cell lung cancer. In this review, we describe early adjuvant trials and highlight the recent landmark studies in this disease. The focus of ongoing and future research efforts is also discussed.