Adjuvant chemotherapy of cisplatin plus vinorelbine had showed a survival benefit over observation alone in a randomized trial ofNCIC JBR10 with 482 patients with Stage IB and Stage Ⅱ NSCLC (NEJM 2005; 352:2589-2597).However, stage IB patients did not derive significantly clinical benefit (HR: 0.94, 95% C.I.0.59-1.50.).The Lung Adjuvant Cisplatin Evaluation (LACE) meta-analysis (J Clin Oncol 26 No 21:3552-3559, 2008) showed a similar result, that stage IB patients did not benefit significantly (HR=0.93, 95% CI 0.78-1.10).Adjuvant Chemotherapy for Stage IB NSCLC remains a controversial issue.Clinical factors and tumor markers which could predict benefit from the Adjuvant chemotherapy in stage IB patients has been explored.It had been reported that p53 protein over-expression predicts the benefit in Stage IB and Stage Ⅱ patients (J Clin Oncol 25, No.33:5240-5247, 2007), and tumor size predicts the benefit for Stage Ⅰ patients (J Clin Oncol 24 (18s):365s, 2006).In this presentation, we showed, that based on NCIC CTG JBR10 database, that the combination of P53 or tumor size information can better predict cisplatin based adjuvant chemotherapys effect than either tumor size or P53 alone in Stage IB NSCLC patients.