Background: Primary dysmenorrhoea has an important effect on women's quality of life. The aim of this study was to determine the epidemiology of primary dysmenorrhea and its relationship with exercise and dietary habits among highschool girls.Material and Methods: In this cross- sectional study, a cluster sample of 200 high-school girls was selected. Data were collected by a researcher-made questionnaire and a Visual Analogue Scale for measuring pain.Results: The prevalence of dysmenorrhea was 91%. The severity of pain has a negative significant correlation with consumption of particles of food and dried fruits and a positive significant relationship with consumption of the cucumber, meat, and dairy products. There was a significant different between severity of dysmenorrhea and doing or not doing exercise.Conclusion: High prevalence of dysmenorrhea and correlation between dietary habits and exercise with dysmenorrhea indicates the necessity for education and more researches around different food regimes.