Benzene is one of volatile environmental pollutants to induce asthma and allergy in respiratory system. The airway epithelium is a physical barrier to inhaled toxicants and particulates. However, the effect of benzene in lung epithelial cell viability has not been elucidated. Thus, this study was conducted to investigate the effect of benzene on apoptosis in A549 cells, lung epithelial cell line. In this study, benzene decreased cell viability of A549 cells in a dose-dependent manner (>10 μM). Benzene-induced decrease of cell viability was blocked by the treatment of antioxidants (vitamin C and NAC). Indeed, benzene induced lipid peroxide formation in A549 cells. Benzene decreased Bcl-2 expression but increased Bax expression in A549 cells. In addition, benzene also increased the cleaved form of caspase-3. In conclusion, benzene induced apoptosis via oxidative stress in cultured epithelial cells.