Aim. An evaluation of lifestyle changes (physical activity, diet) in patients after breast cancer surgery. Materials and method. 200 women after breast cancer surgery were surveyed. The respondents were asked whether the surgery caused a change in their diet and physical activity. An analysis was performed concerning the education, place of residence and age of the respondents. Results. Prior to being diagnosed with breast cancer, about one third of the respondents were concerned about their diet and physical activity. After the surgery more than a half of the respondents were concerned about a healthy lifestyle. Women below 50 years old with higher education, who live in a city, were concerned about their diet and physical activity both before and after surgery. Conclusions. As a result of the breast cancer surgery, lifestyle changes were most often found in women aged 50-69 years old with higher education who lived in a city. Statistical relevance of the results was noted.