Abstract: Although surgery is regarded as the best possible treatment for patients with early stage nonsmall cell lung cancer（NSCLC）， only 20％-25％ of patients have resectable disease at presentation. Despite optimal surgical treatment， 5-year survival rates in patients with resectable NSCLC are historically modest（40％）. Adjuvant chemotherapy has been a standard treatment after complete resection in early stage NSCLC，and 4％-15％ patients can benefit from it. In recent years， although multiple randomized trials assessing the efficacy of adjuvant chemotherapy for stage ⅠB NSCLC have been reported， the benefit of adjuvant chemotherapy in patients with stage ⅠB NSCLC is controversial. Herein， we review the results of the major adjuvant chemotherapy trials and find the highrisk patients and their implications for the treatment of stage ⅠB NSCLC.