Limited study of persistent organochlorine pesticides (OCPs) and endometriosis has been conducted. One hundred women aged 18-40 years who were undergoing laparoscopy provided 20 cc of blood for toxicologic analysis and surgeons completed operative reports regarding the presence of endometriosis. Gas chromatography with electron-capture was used to quantify (ng/g serum) six OCPs. Logistic regression was utilized to estimate the adjusted odds ratios (aOR) and 95% confidence intervals (CI) for individual pesticides and groups based on chemical structure adjusting for current cigarette smoking and lipids. The highest tertile of aromatic fungicide was associated with a five-fold risk of endometriosis (aOR = 5.3; 95% CI, 1.2-23.6) compared to the lowest tertile. Similar results were found for t-nonachlor and HCB. These are the first such findings in a laproscopic cohort that suggest an association between OCP exposure and endometriosis. More prospective studies are necessary to ensure temporal ordering and confirm these findings.