Hobo R, et al. - This study is performed to explore the utility of the endometriosis fertility index (EFI) for predicting the ability to conceive without assisted reproductive technology (ART) treatment after laparoscopic surgery. The outcome of this study suggests EFI possesses greater predictive power for a successful pregnancy with natural intercourse or intrauterine insemination in infertile patients, regardless of endometriosis than the Revised-American Society of Reproductive Medicine classification.