To know the diagnostic precision of ultrasound in the detection of ovarian endometriosis. This is a retrospective study of diagnostic accuracy of prospectively collected data from patients with pelvic pain who underwent a transvaginal ultrasound before surgery, performed by gynecologists experts in ultrasound. This study was conducted in a tertiary-level teaching hospital. Data was collected between January 2018 and January 2021. Laparoscopy afterwards was the gold standard used in this study. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and likelihood ratio were calculated. A total of 290 patients underwent ultrasound at our institution. 214 women were excluded because they did not have the appropriate preparation for the mapping ultrasound for endometriosis. Thus, a total of 76 patients were finally included, of these 38 had confirmed ovarian endometriosis, of which 11 were bilateral. The ultrasound had a sensitivity, specificity, positive and negative predictive values, likelihood ratio positive and negative of 95, 94, 95, 94, 17,1 and 0,05 respectively. Ultrasound mapping for the detection of endometriosis showed a good diagnostic performance.