Introduction: Premenstrual syndrome (PMS) is a psycho-somatic problem, which occurs in the late phase of the menstrual cycle. Many women suffer from the symptoms of this syndrome. The aim of this study was to evaluate the frequency of PMS and its relationship with exercise among the students of Bushehr University of Medical Sciences.

Methods: A cross-sectional descriptive analytical study was designed in 2016 and 408 students were selected by the stratified random sampling from five faculties of Bushehr University of Medical Sciences. Data were collected through the standard premenstrual syndrome questionnaire (PMSQ) and international physical activity questionnaire (IPAQ). Descriptive statistics, ANOVA, independent sample t-test and Chi-square test were used to analyze the data.

Results: The mean age of the participants was 21.77± 2.45. And, the prevalence of PMS was 83.5%. Approximately 48, 41 and 11% of the participants had, respectively, weak, moderate and severe physical activity. There was no significant relationship between the frequency of PMS and physical activity (p=0.384), but the severity of anxiety (p=0.041), anger (p=0.012), migraine (p=0.018), abdominal blotting (p=0.042) decreased with doing physical activity.

Conclusion: The prevalence of PMS among the students was high. About half of them had weak physical activity. It seems that planning health education and physical activity programs can be effective in moderating the sumptoms of PMS.