Purpose: This study described the design and development of a cohort study established to investigate the ovarian aging process and its impact on women's health.Methods: A community-based prospective cohort study of middle-aged Chinese women was initiated in 2005 and is ongoing. Sociodemographic characteristics, menstrual calendars, and medical histories were recorded at baseline and at annual follow-ups. Physical measures, blood sampling, bone status assessment, and body composition evaluation are likewise performed annually.Results: A total of 954 women with a median age of 47years were enrolled. At baseline, 44.7% were reproductive, 25.4% were in menopause transition and 30.0% were postmenopausal. Among them, 37.0% were overweight, 16.9% were obese, and 17.7% had hypertension. Nearly half of all subjects have been followed up five or more times. The median duration of menopausal transition was 17.5months. The median natural menopausal age ascertained by follow-up interviews was 52.0years, which is significantly older than the median recalled age of 50.0years.Conclusions: This is the first population-based prospective cohort study exploring the ovarian aging process in Chinese women. A large sample size and long follow-up duration were achieved. Detailed analysis of data obtained from this cohort will be provided in future reports.