Data from laboratory animals and primates suggest that environmental contaminants such as dioxin might be associated with the etiology of endometriosis. The extent to which these findings might be relevant for human females remains elusive and served as the impetus for study. The purpose of this exploratory study is twofold: 1) to identify polychlorinated biphenyls congeners and pesticides that discriminate women with and without endometriosis and (2) to determine which, if any, of these environmental contaminants predict risk of endometriosis (RO1ES0904501). The study sample comprises 85 women undergoing laparoscopy or laparotomy for diagnosis and/or treatment of endometriosis (n=32), other gynecologic pathology (n=30) or tubal sterilization (n=23). In-person interviews were conducted with all women in advance of surgery, and blood specimens for the analysis of 66 congeners of PCBs and 7 pesticides were obtained from 81 consenting women. Toxicological analyses were conducted using gas chromatography with electronic data capture. Data analysis is currently underway.