Background : Regular menstrual cycles in women are 24-35 days. One of the causes of menstrual disorders is exercise. This relates to students who join sports clubs actively. They exercise intensively without regard to the duration and pattern of the menstrual cycle as well as its intensity. The frequency and duration of exercise should also be a concern because it can disrupt the menstrual cycle. Research Purposes : This study aimed to investigate the correlation between sports activity and the menstrual cycle of athlete. Research Method : The data collection technique used the total sampling method. The type of research was observational analytic and cross-sectional research design. The study sample consisted of 36 sport womens aged 15-25 years. The research instrument used the Baecke 1982 questionnaire and menstrual calendar. The statistical test employed the Spearman-Rank correlation. Results : The results of this study showed that the correlation between sports activity and the menstrual cycle of athlete was moderate with the score obtained, p = 0.005 (p <0.01) and r = -0.456. Conclusion : There was a correlation between sports activity and the menstrual cycle of athlete. The negative correlation means that the more active the sports activity the more irregular the menstrual cycle.