Chemotherapy and targeted therapy remain the cornerstone of treatment of locally advanced and metastatic non-small cells lung cancer (NSCLC). Given the intrinsic chemoresistance of tumor cells, new treatment options have been developped. The knowledge of the molecular mechanisms of tumor biology, and signal transduction pathways activating cancer cells led to the identification of a new targeted therapy such as Crizotinib. The small molecule Crizotinib is a selective inhibitor of the receptor tyrosine kinase ALK (anaplastic lymphoma kinase) and its oncogenic variants (ALK fusion gene and some mutations of ALK). Phases I and II trials showed the efficacy of Crizotinib in the treatment of locally advanced and metastatic NSCLC expressing ALK. Thereafter, randomized Phase III trial confirmed the significant superiority of Crizotinib versus standard chemotherapy in terms of progression free survival and objective response with good tolerance; therefore, it has been approved by the Food and Drug Administration (FDA) as the standard treatment for locally advanced and metastatic ALK-positive NSCLC.