Introduction:
Breast cancer is one of the most common malignancies among women in Poland, as well as worldwide. It is important to have knowledge concerning prevention of breast cancer. Health behaviours which exert an indirect effect on the state of health are also essential.

Objective:
The aim of the study was assessment of health behaviours and knowledge concerning prevention of breast cancer among young adults.

Material and methods:
The study was conducted anonymously among 203 adult high school students in the Kuyavian-Pomeranian Province. The respondents completed standardized Healthy Lifestyle and Self-Control Questionnaire (HLPCQ) and an author-constructed questionnaire. Calculations were performed using IBM SPSS software.

Results:
The results of the HLPCQ showed that the respondents rated the area of ‘daily routine’ the highest, while ‘dietary harm avoidance’ the lowest. The mean overall HLPCQ score was 58.13. The majority of respondents were familiar with breast examination methods, and had knowledge about breast selfexamination. As many as 77% of respondents considered that among Poles the awareness of contracting breast cancer is average. The most familiar symptom was a palpable lump inside the breast. On the other hand, the most frequently reported risk factor increasing the occurrence of breast cancer was the genetic factor. This is an alarming fact that more than 80% of the respondents had never talked to a doctor about breast exam, and nearly 90% had never breast ultrasound performed.

Conclusions:
Students do not have full knowledge of preventive measures, and require deepening their knowledge in both theoretical and practical terms. There is a need for increasing the involvement of health care professionals in education about breast cancer prevention and health behaviours.