|Lung cancer is the leading cancer worldwide in terms of incidence and mortality. Although lung cancer remains the leading cause of cancer-related mortality in the United States, its incidence is decreasing. It may due to better prevention, awareness and early detection. Tobacco use is the main risk factor for lung cancer. Radon, arsenic, asbestos, heavy metals-chromium VI, nickel, cadmiumcoke oven and coal gasification fumes and soot are well-known lung carcinogens. Several studies reported that high fat consumption increases the risk of lung cancer. Exposure to incense smoke and exposure to fry pan fumes were associated with a higher risk for lung cancer due to the presence of combustion-related carcinogens. Another study showed that heavy pesticide usage was associated with increase of lung cancer.