Background: Primary dysmenorrhea is chronic cyclical pelvic pain associated with menstruation in absence of an identifiable pathological condition. The purpose of this study was to compare the prevalence and severity of dysmenorrhea among athletes and non-athlete girls and its relation with body composition.

Materials and Methods: In this cross sectional study 223 healthy students aging 20-30 years old from Guilan university randomly divided to two groups (72 athletes and 151 non-athletes). The athletes group engaged in regular physical activity for at least one year, three sessions a week and the non-athletes group were not engaged in any sports activity.  Data were collected by questionnaire and anthropometric measurements.

Results: The prevalence of dysmenorrhea was lower in athletes than non-athletes group (61.1% vs. 88.8%, p<0.001). A significant difference was observed in mood symptoms, physical symptoms and severity of pain between two groups (p<0.05). Also there was statistically significant relationship between body fat and physical symptoms of dysmenorrhea in both groups. However, no statistically significant relationship was observed between physical symptoms of dysmenorrhea, BMI and WHR.

Conclusion: It seems that performing regular exercise can be used as a preventing, treating or supplementary method in control of the early dysmenorrhea.