Lung cancer is the leading cause of cancer-related deaths worldwide. While cigarette smoking is of key importance, factors such as diet also play a role in the development of lung cancer. MedLine and Embase were searched with diet and lung cancer as the key words. Recently published reviews and large well designed original articles were preferred to form the basis for the present article. A diet rich in fruit and vegetables reduces the incidence of lung cancer by approximately 25%. The reduction is of the same magnitude in current smokers, ex-smokers and never smokers. Supplementation with vitamins A, C and E and beta-carotene offers no protection against the development of lung cancer. On the contrary, beta-carotene supplementation has, in two major randomised intervention trials, resulted in an increased mortality. Smoking remains the leading cause of lung cancer. The adverse effects are only ameliorated to a minor degree by a healthy diet.