Background: Educating women regarding breast cancer and increasing breast self-examination
uptake continues to remain a major challenge despite the intensive campaigns. The provision of
health information via Whats App media can increase knowledge about breast cancer and improve
health. Aim: To evaluate the effect of app reminder massages on knowledge and practices regarding
breast self-examination among adolescent female students. Design: A pre/post-quasi-experimental
research design was utilized. Sample: A multi-stages technique of purposive sample included 300
adolescent female students selected from two secondary schools at Fayoum City. Tools: (1) A
structured interview questionnaire, (2) pre & post-knowledge assessment sheet related to breast
cancer and breast self-examination and (3) Breast self-examination (BSE) observational checklist,
and (4) Satisfaction sheet related to WhatsApp reminder massage. Results: There was a
statistically significant difference between adolescent student's knowledge pre and post what app
reminder messages regarding breast self-examination, As regards sources of information about
breast cancer, the main source was the media, a statistical improvement was found regarding the
BSE checklist pre and post what app reminder massages, there was highly statistically significant
(P=0.004, P=0.005) positive correlation between total knowledge scores and practices after one
month what app reminder messages implementation. Conclusion: What App reminder messages
had a positive effect on improving knowledge and practice of breast self-examination among
adolescent students. Recommendations: What App reminder massages can be a viable tool that
can be used by healthcare workers to educate Adolescent girls regarding breast cancer and breast
self-examination and well-informed continuous; health education program should be imparted to
adolescent girls.