Cancer has become a major public health issue. It is thus crucial to measure the general population's behaviours, opinions and perceptions about cancer and its associated risk factors. This article describes some of the main findings of a 2005 French survey (n = 4,046). Cancer is considered by a large majority to be the most serious disease, far before HIV/AIDS and cardiovascular diseases. The carcinogenic risk that is associated to main risk factors, such as sun exposure, tobacco-smoking and alcohol use appears to be well-known. However, many people justify dangerous behaviours with strongly-anchored beliefs, which maintain dangerous behaviours for health on the long-term. What's more, the perception of risk proliferation can also generate risk denial. Because self-exempting beliefs are still widespread within the general opinion, it is essential to continue public health information campaigns dedicated to cancer prevention, so as to induce better prevention practices within the general population and to reduce stigmatisation and isolation experienced by cancer patients. If risk denial is not systematically a consequence of a lack of information, it is generally associated to a cognitive construction that gives coherence to behaviours.