In moderate to severe pelvic endometriosis, the CA-125 at 30 UI / ml was associated with high sensitivity (93.2%), high specificity (90%), and the best area under the ROC curve compared to other cutoff levels, hence suitable for diagnosis. Conclusions: Serum CA-125 test was associated with high sensitivity, specificity and positive predictive value for moderate to severe pelvic endometriosis, suitable for planning pre - and post-operative strategy.