Objectives: To evaluate the perception of knowledge of the ways of detecting breast cancer in a sample population of South and Southeast. Methodology: Research involving 2100 women aged above 18 years by applying multiple choice questionnaire with 11 questions and held for 30 interviewers on 03.16.2015, in places of great circulation in São Paulo, Rio de Janeiro and Porto Alegre. Results: Overall, 55% of women knew someone who has had breast cancer and 20% had a positive family history. Only 9% had personal history of breast cancer and of these, we find the following proportion of tests that aroused the suspicion of the disease: mammography (37%), ultrasound (21%), self-examination (17%), MRI (14%) and clinical examination (11%). Among the 91% of women who had no personal history of breast cancer, 56% had done some test to detect changes in the breast, mammography highlighting (36%) and ultrasound (20%). Interestingly, the best way to detect breast cancer related was the ultrasound (67%), followed by mammography (60%), MRI (48%) and self examination (47%). 87% believe that breast cancer is curable and 80% that the best way is with early diagnosis. Conclusions: The results brought a positive outlook on the perception of women on ways to prevent breast cancer; 56% of respondents had already done some test to detect breast changes, about 90% that the disease is curable and 80% that the best way to cure is early diagnosis.