Overwhelming evidence has been presented for the influence of nutrition on the development of malignant neoplasias in several organs. About every third case of cancer has been estimated to have been induced by nutrition. A contribution of nutrition rich in energy to fast growth of the body, increased height of adults and the early onset of menarche has been postulated. All of these variables are convincing factors for a higher incidence of breast cancer. Adipositas is also a convincing risk factor for the development of cancer in the endometrium and probably increases the risk of cancer in breast and kidney. The risk of colon and rectum being affected by cancer is possibly elevated by adipositas. Reduced physical activity increases convincingly the risk of malignant colorectal neoplasias and possibly that of lung and breast cancer. Elevated intake of refined sugar contributes possibly to an increase of risk for cancer of the colon. High consumption of saturated fatty acids and cholesterol is a possible risk factor for carcinomas of the lung, the colon and the breast. Cholesterol alone enhances possibly the incidence of cancer in the endometrium and prostate. Alcohol consumption is a convincing risk factor for the development of cancer found in mouth, pharynx, larynx, and the cirrhotic liver. Furthermore, alcohol intake probably enhances the likelihood to be taken ill with cancer of the colon, rectum, and the breast in a dose-dependent manner. It also possibly enhances carcinogenesis in the lung. Red meat probably increases the risk for colorectal carcinoma and possibly that for cancer in the breast, pancreas, prostate, and kidney. In addition to direct nutritional factors, substances may be involved in the pathogenesis of cancer that originate from air pollution, food preparation or storage of food. Compounds that have to be mentioned in this context are nitrate from manure, benzpyrene from smoke and mycotoxins, which are formed as a result of fungiform contaminations.