Background: Warning signs of cancer have long been used as an effective way to summarise and communicate early indications of cancer to the public. Given the increasing global burden of cancer, the communication of these warning signs to the public is more important than ever before. Aim: This paper presents part of a larger study which explored the attitudes, knowledge and behaviours of people in mid-life towards cancer prevention. The focus of this paper is on the assessment of the knowledge of members of the public aged between 35 and 54 years of age. Method: A questionnaire was administered to a representative sample of the population listing 17 warning signs of cancer. These included the correct warning signs and distracter signs. Respondents were asked to correctly identify the seven warning signs. Results: Findings show that respondents could identify 4.8 cancer warning signs correctly. Analysis by demographics shows that being female, being older, having a higher level of educational attainment and being in a higher socio-economic group are predictors of better level of knowledge of cancer warning signs. Recommendations: Recommendations are proffered with regard to better targeting, clarification and communication of cancer warning signs. (C) 2010 Elsevier Ltd. All rights reserved.