Introduction and Purpose of the Study.- Research over the past forty years has highlighted the role of nutrition in the development of certain cancers. It is now recognized that excessive consumption of red meat and processed meats, alcoholic beverages, salt and salty foods, beta-carotene supplements, as well as being overweight and obese, increases the risk of cancer. Conversely, physical activity, fruits and vegetables, and breastfeeding reduce this risk. The 2010 Cancer Barometer examined perceptions of cancer risk associated with certain nutritional factors, perceptions that may play an important role in the adoption of behaviors that are more or less conducive to health. The objective here is to analyze these perceptions. Materials and Methods.- The 2010 Cancer Barometer was conducted among a random sample of 3,727 French-speaking individuals aged 15 to 85, representative of the population residing in metropolitan France. The survey was conducted by telephone (landlines, cell phones, and "unbundled" lines). Variations in perceptions of cancer risk according to several sociodemographic factors were analyzed using logistic regressions among those aged 15–75. Results.- The increased risk of cancer associated with frequent consumption of red meat is known by 30.2% of the population. This is the case for 37.0% of individuals regarding salt or salty foods, 47.4% regarding processed meats, and 63.6% regarding being overweight or obese. Protective factors are identified as such by 55.9% of individuals regarding frequent consumption of fruits and vegetables and by 58.8% regarding regular physical activity. The positive influence of breastfeeding on the risk of breast cancer in the mother is known by 23.8% of women. Perceptions of cancer risk factors are socially determined. In multivariate analysis, the protective effects of fruits and vegetables and physical activity, and the harmful effects of frequent consumption of red meat, processed meats, and salt or salty foods, are better known among individuals with higher educational attainment and income. A poorer understanding of the influence of fruits and vegetables (OR=0.7; p < 0.05) and processed meats (OR = 0.6; p < 0.01) is also observed among the unemployed. The increased risk of cancer associated with being overweight or obese is better understood by individuals with higher incomes. Finally, the protective effect of breastfeeding against breast cancer in the mother is cited more frequently by women with a level of education higher than a high school diploma (OR = 2.3, p < 0.001). Conclusion.—Overall, a relatively large number of individuals are unaware of the influence of certain nutritional factors on cancer risk. These results raise questions about how to improve the effectiveness of nutritional cancer prevention. Public statements by the media, institutions, and expert groups could be considered. Messages about cancer risk factors, including nutritional factors, could also be disseminated to the public. Source: poster cited in the journal "Clinical Nutrition and Metabolism" in Supplement 2, Issue 25.