Purpose: This study was conducted to investigate the relationship between nursing and midwifery undergraduate students’ health beliefs and breast cancer knowledge levels and breast self-examination (BSE) behavior. Materials and method: This study was based on a cross-sectional research design and conducted in a Web environment. Four hundred and forty-eight female students were included who study in the 3rd or 4th years of the nursing and midwifery departments. Research data were collected between December 2020 and January 2021 by utilizing the Introductory Information Form, the Champion’s Health Belief Model Scale, and the Comprehensive Breast Cancer Knowledge Test. Results: It was revealed that 52.7% of the students performed BSE on a regular basis. Based on the practice of BSE, it was found that there was a statistically significant difference between the mean scores of benefits, obstacle perception, confidence/self-efficacy, and motivation subscales of CHBMS (p < 0.05). In terms of the risk of not performing BSE among students, having an extended family increased the risk by 3.29 times, not applying a clinical breast examination by 6.53 times, and a 1-unit increase in weighted GPA by 2.18 times; a 1-unit increase in the obstacle perception score related to BSE practice increased risk by 1.11 times. Conclusion and recommendations: Nurses’ and midwives’ health beliefs, attitudes, and behaviors should be improved with regard to the importance of breast cancer and BSE throughout their education, so that they can be role models for preventive healthcare practices in society.