Apoptosis is natural process in the development and maintenance of multicellular organisms. However, tumor cells often have faulty apoptotic pathways. The defects of apoptosis are partially caused by mutation and aberrant expression of apoptotic proteins. The apoptosis inactivation is implicated with both tumorigenesis and drug resistance. In addition, as compared to small-cell lung cancers, non-small cell lung cancers are less sensitive to radiation treatment or chemotherapy. Therefore, understanding the mechanisms of apoptosis induction in lung cancer cells is very important for anti-lung cancer drug development and lung cancer therapy. In this review, we discussed about the apoptosis mechanisms and altered apoptosis regulators expression and gene mutation in lung cancer.