The SWAN Repository is a biologic specimen bank of the Study of Women’s Health Across the Nation (SWAN). The SWAN cohort was recruited in 1996/1997 and consists of 3302 African-American, Caucasian, Chinese, Hispanic, and Japanese women. The SWAN Repository contains more than 350,000 blood and urine specimens generated from the study participants’ annual visits (8 visits to date), at which time medical and health history, psychosocial measures, biological measures, and anthropometric data were and are being collected. In addition, a subset of the participants are providing urine samples, collected daily over the length of one menstrual cycle, each year. More than 900,000 of these samples are in the SWAN Repository and are available to researchers who wish to study the midlife and menopausal transition. Additionally, a DNA sample repository is also available and includes DNA as well as transformed B-lymphoblastoid cell lines from more than 1800 of the participants.