Background/Aims: To determine whether the revised American Fertility Society (rAFS) classification and endometriosis fertility index (EFI) predict pregnancy rates (PRs) in patients with surgically confirmed endometriosis attempting natural conception. Methods: We retrospectively assessed 194 women with endometriosis who underwent laparoscopic surgery; 161 women completed the follow-up. Pregnancy outcomes, rAFS stages and EFI scores were documented. Cumulative PRs were compared using Kaplan-Meier survival analysis. Results: The cumulative PR 36 months after surgery was 46.6% (stage I, 53.6%; stage II, 36.0%; stage III, 51.7%, and stage IV, 41.7%; log-rank test, χ2 = 4.143, p = 0.246). In the 1st year, PRs significantly differed between patients with rAFS stage IV and those with stages I-III (Pearson's χ2 test, χ2 = 6.024, p = 0.014). Significant differences in cumulative PRs were observed among EFI scores (group 1, EFI score 0-3, 8.3%; group 2, EFI score 4-7 41.2%, and group 3, EFI score 8-10 60.9%; log-rank test, χ2 = 16.254, p < 0.001). Conclusions: EFI scores, but not rAFS stage, predict PRs in patients with endometriosis-associated infertility. EFI scores may be used to guide postoperative treatment.