Introduction : Chemoresistance is a major challenge in the treatment of advanced non-small cell lung cancer (NSCLC). As the Sonic Hedgehog (Shh) pathway is reactivated in NSCLC, we investigated an association between chemoresistance and Shh activation. Materials and Methods : From a cohort of 178 patients with advanced NSCLC treated with platinum-based chemotherapy as first-line treatment, we selected all surgical tumor samples at diagnosis (n=36). Shh activation was evaluated through Gli1 and Gli2 expression by immunohistochemistry (IHC) (quantitative score). In vitro treatment studies with cisplatin, vismodegib (Shh-pathway inhibitor) or both were performed on NSCLC cell lines (H322 and A549) and on primary cultures from patients with sarcomatoid carcinoma (n=4). Results : Twelve patients were refractory to chemotherapy (r-patients, 33.3%) and 24 had controlled disease (c-patients). Gli1 expression did not differ between the r- and c-patients (p=0.35). Gli2 expression was more often positive in the r-patients (41.7% versus 8.3%, p=0.02). Progression-free survival (PFS) and overall survival (OS) in patients with Gli2-positive score were 2.1 and 8.0 months, respectively, versus 6.7 and 18.0 months in patients with Gli2-negative score (p=0.03; p=0.002). In multivariate analysis, Gli2 score was independently correlated with PFS (hazard ratio [HR]=2.64; 95% confidence interval [CI]: 1.05-6.63; p=0.04) and OS (HR=4.36; 95% CI: 1.67-11.36; p=0.003). The sarcomatoid carcinoma cell lines were more resistant to cisplatin than the H838 and A549 cell lines. The cisplatin - vismodegib combination displayed a synergistic cytotoxic effect in the most chemoresistant cells in vitro. Conclusion : The Shh pathway is associated with resistance to platinum-based chemotherapy in NSCLC.