Background:   Breast cancer (BC) is the most common cancer among females worldwide. Breast self-examination (BSE) is accepted, cheap, simple, accessible, non-invasive screening methods for early detection, helping in reducing morbidity and mortality and improving prognosis of breast cancer.  Aim: Assessments of the knowledge, attitude and practice of women toward breast self-examination to help in the future reduction of prevalence of breast cancer and promote women health. Subjects and methods: A cross sectional study was done on 420 females ≥20 years old attending primary health care services in Zagazig district of Sharkia Governorate. Data were collected through structured questionnaire to assess the sociodemographic data, knowledge, attitude, and practice of women toward breast self-examination (BSE). Results: The level of satisfactory knowledge, attitude, and practice towards BSE; 24.3%, 27.4% and 22.9% respectively and it was highamong highly educated, professionally working and those with positive family history of BC with statistically significant association. Most common source of information of women about BSE was mass media (49%) and (63%) were practicing BSE irregularly. There were statistically significant association between knowledge, attitude, and practice. Conclusion and recommendation: There waslow level of satisfactory knowledge, attitude and practice towards BSE among participants, and (63%) of those practicing BSE did it irregularly. So, we recommend regular health education program to all females ≥20 about BC and importance of BSE in early detection and training them on how to perform it properly and regularly in simple and clear way.