This study aims to analyze the correlation of body mass index with the regularity of the menstrual cycle of young women in The City of Parepare. A total of 60 young women age 17 to 19 years participated in this study. The body mass index and regularity of the subject's menstrual cycle were evaluated. In body mass index distribution, young women with normal nutritional status were more likely (48.3%), compared with thin nutritional status (33.3%) and nutritional status (18.3%). Regular menstrual cycle more normal young women (56.7%) compared to abnormal (43.3%). The results of this study indicate that there is a relationship between body mass and regularity of the menstrual cycle in young women.