Context: Breast cancer is the main type of cancer affecting women and the fourth most common cancer mortality cause. Approximately one out of eight women worldwide develop breast cancer. Screening prevention plays a vital role in the early detection of breast cancer and reducing mortality rates. Aim: The study aimed to evaluate the effect of the health belief model-based education on breast cancer preventive behaviors. Methods: Quasi-experimental (pre/post-test) design was used in this study. The study was conducted at the obstetrics outpatient clinic affiliated to Benha University Hospital, Egypt, on a purposive sample of 100 women. A self-administered questionnaire, Champion’s Health Belief Model Constructs Scale (CHBMS), and an observation checklist for Breast Self-Examination (BSE) were used to collect the data. Results: The study showed that 62% of the studied women’s mean age was 35.90±6.45, 53 % of them had secondary education, 93% of them didn't do regular breast self-examination, and 96% of them did not have a mammogram ever. Besides, there were improvements in the studied women' knowledge scores regarding breast cancer post-model implementation (P < 0.001). There was a highly statistically significant difference in total practice scores of preventive behaviors pre and post model implementation (p-value