Breast cancer is the most frequent cause of death from malignant tumors amongst women in Poland. There was 12049 new cases of malignant breast cancer and 4887 deaths caused by the disease in 2004 year. However prevention examinations such as mammography, ultrasonography and palpation examination allows for early detection of neoplasm's changes, breast cancer is still the main cause of death. The main predisposing factors for pronouncement of breast cancer are age, early menarche, first pregnancy in late age, or lack of pregnancy, short period of breast feeding , late menopause, family history as well as diet and mode of life. In opinion of oncologists, about one third of tumor case diseases’ reasons, are errors in nutrition, so even small changes in diet can decrease risk of breast cancer. Amount and kind of consumed fat has major influence . It exerts protecting influence of long chain unsaturated fatty acids on development of breast cancer. There is a correlation between BMI and breast cancer risk. Obesity increases the risk of local recurrence of cancer process and also has an influence on survival without any syndromes of disease. Limits of food’ s caloricity as well as increase of physical activity causes reduction of body mass which is connected with decreased risk of cancer. Besides, increased consumption of carbohydrates correlates with increased morbidity risk. Observation research show that regular physical activity, maintaining of proper body weight and limitation of alcohol intake in diet allows to reduce breast cancer risk.