To investigate the correlation between menstrual cycle and follicular maturation process in patient with polycystic ovary (PCO) from the prevalence of menstrual cycle abnormalities.To determine the correlation between menstrual cycle and fol- licularmaturation process in patient with polycystic ovary at Asri Medical Center Yogyakarta, Indonesia. Methods This study was a retrospective analytical approach with case control study. The study population was female patients in the Department of Obstetrics and Gynecology Asri Medical Center Yogyakarta, Indonesia. While the sample in this study 178 female patients in 2014 at Department of Obstetrics and Gynecology Asri Medical Center that meet the inclusion and exclusion criteria and using total sampling technique. Retrieving data using instruments from medical records. Data were analyzed using chi-square analysis