Trans, trans-2,4-decadienal (tt-DDE), a specific type of dienaldehydes, is abundant in heated oils or cooking oil fumes. Ingestion of heated oils and exposure to cooking oil fumes has been suggested to have great health impact in variety of organs, including lung. We demonstrated that long-term treatment with tt-DDE increased cell proliferation and cytokines secretion via oxidative stress in human bronchial epithelial cells BEAS-2B. Furthermore, these effects were prevented by co-treatment with anti-oxidants N-acetylcysteine (NAC) and Vitamin C. Utilizing the proteomic techniques, the objective of this study was to identify protein biomarkers associated with tt-DDE-induced oxidative stress and cytotoxicity in human bronchial epithelial cells BEAS- 2B. Treatment with tt-DDE for 48 h dose-dependently reduced cell viability in human BEAS-2Bcells, but not in lung cancer cell lines. Co-treatment with antioxidant Nacetylcysteine tremendously reduced tt-DDE-induced in BEAS-2B cells. Protein extracts from DMSO or tt-DDE treated cells were separated on 2D gel and differentially expressed proteins were identified by mass spectrometry. A total of 30 proteins with known functions were identified