Background: Ministry of Health Republic of Indonesia in 2015 declared cervical cancer is cancer with highest prevalence in Indonesia in 2013, that is equal to 0,8%. Ministry of Health of Indonesia noted D.I province of Yogyakarta is one of the provinces in Indonesia with the highest prevalence of cervical cancer incidence of 2.4% of cases. Research Objective: This study aims to determine the effect of health education on the level of knowledge About Cervical Cancer Prevention in MAN 3 Sleman . Research Method: The tpe of research used quantitative research, pre-experimental research design with one group pretest-posttest design. The sampling technique using total sampling and the number of respondents were 86 students. This research using a questionnaire level knowledge of cervical cancer prevention this is a questionnaire that was adopted by researchers from Sylvina 2012 which contains 15 questions with 5 multiple choice questions and 10 questions statement agree and disagree. Result: his study uses Wilcoxon test to determine the effect of peer education on the level of adolescent knowledge about cervical cancer prevention in MAN 3 Sleman. The results obtained p = 0.000, p> 0,05 so concluded there is influence from health education to level of knowledge of school children about cervical cancer prevention at MAN 3 Sleman. Conclusion: There is an influence of health education on the level of knowledge of school children about the prevention of cervical cancer in MAN 3 Sleman