To analyze the knowledge of the facts on the part of the female population of Mallorca with regard to the causes of cancer, the beliefs regarding diagnosis and treatment and their attitude toward prevention. A descriptive cross-section study of a random population sample (n = 124) of women within the 40-69 age range. The questionnaire includes socio-demographic variables, risk factors, early warning symptoms and beliefs regarding diagnosis and treatment and attitudes toward prevention. Cigarette smoking (92.7%; CI:88.1-97.3) and drinking alcoholic (85.7%; CI:79.4-92.0) are the most well-identified causes. Also the presence of a lump in the breast (92.6%; CI:87.9-97.2) and changes in a mole or wart on the skin (89.7%; CI:84.2-95.2%). The underestimate the role of the diet (44.4%; CI:35.1-53.8) and overestimate the environmental factors. The knowledge and use of self-examination procedures on the breast are associated directly with the degree of education (p < 0.05). Most believe that early diagnosis improves the prognosis (IC:94.2-99.5) and that treatment is beneficial (85.2%; CI:78.5-91.9). They consider surgery to be the most highly effective method, and in the event of any doubt they would first see their primary care physician (41.9%; CI:33.2-50.6). It is mainly older women having a low level of completed schooling who get their information regarding cancer above all from the television (43.5%; CI:34.8-52.3). Worthy of special mention is the very small impact of health care personal as a source of information (6.5%; CI:2.1-10.8). A major knowledge of the facts exists regarding the causes and warning signs, although some misconceptions do exist. In view of future prevention campaigns, educational measures addressed mainly to older women having a low level of completed schooling should be carried out.