Representation is an act of thought through which a subject relates to an object. There is no representation without an object. In order to comprehend the representation’s content, it is thus necessary to emphasize on the components from the representations which scientific information belongs to and that is of great interest for us on this study on cancer. This study aims to identify the cancer’s representations that 10 years old pupils possess (in Year 5). The variable taken into account in this study is the knowledge of cancer these young pupils have and its relative position compared with other illnesses. The sample is composed of 64 pupils from Year 5. The pieces of information were gathered from the filing systems intuitively established by the pupils (Intuitive classifying systems). A first questionnaire (pre-study) required listing the names of the illnesses that come straight to their minds. The second questionnaire suggested 4 features (contagious illness, fatal, curable with or without medicines) and asked to classify illnesses according to the latter. The results showed the strong importance of cancer in the pupils’ minds while they should feel less concerned about it, particularly because this subject is not seen at school at this age. Cancer is the most spontaneously quoted illness before influenza and HIV. It is perceived as non-contagious (For 92% of the pupils) but highly associated to death (89%) even though the chances of survival are higher than for the other illnesses evoked (HIV, influenza, Ebola) thanks to a treatment (30% of the answers). This relation to cancer seems to be correlated to the personal background of the pupils, who were touched by this illness in their close relations, as cancer is often presented as really serious without being explained with simple explanations. These results raised the importance of teaching and giving detailed information in the school or extracurricular environments to young people. It is hoped that such an education would demystify cancer.