Study Objective Laparoscopic ureterolysis, an advanced laparoscopic skill, is difficult to predict pre-operatively, particularly in the absence of hydroureter or hydronephrosis on pre-operative imaging. This study assessed whether transvaginal ultrasound (TVU) markers (endometrioma, Pouch of Douglas ‘POD’ obliteration, uterosacral deep endometriosis ‘USL DE’ or ovarian fixation) are significantly associated with ureterolysis in women with suspected endometriosis. Design Prospective multicentre study assessed the diagnostic accuracy of TVU markers including endometrioma, POD obliteration, USL DE and ovarian fixation in predicting laparoscopic ureterolysis in women with suspected endometriosis who underwent laparoscopic surgery at Liverpool and Campbelltown Hospital during 2020-21 period. Setting N/A. Patients or Participants 63 women with suspected endometriosis were recruited. Interventions Participants underwent a specialised TVU by an expert sonologist, followed by laparoscopic surgery within 6 months by an advanced laparoscopic surgeon, who documented the intraoperative and histopathological findings. Measurements and Main Results The mean age was 35. 31/63 (49%) women with suspected endometriosis required ureterolysis, 14/31(45%) complete ureterolysis and 17/31 (55%) partial ureterolysis (for the excision of localised peritoneal endometriosis over the pelvic side wall). Of the 14 women requiring complete ureterolysis, 11/14 (Sensitivity ‘Sn’ 78.57%, accuracy ‘Ac’ 53.97%, p0.13) had fixed ovaries, 8/14 (57.14%, Ac 77.78%, p0.0042) had POD obliteration, 7/14 (Sn 50%, Ac 79.37%, p0.0052) had endometrioma and 6/14 (Sn 42.86%, Ac 74.60%, p0.0634) had USL DE on TVU. Of the 17 women requiring partial ureterolysis, 8/17 (Sn 47.05%) had fixed ovaries, 5/17 (29.41%) had USL DE, 3/17 (17.65%) had POD obliteration and 1/17 (5.88%) had endometrioma on TVU. Conclusion POD obliteration and endometrioma on TVU are significantly associated with the need for ureterolysis in women undergoing laparoscopy for suspected endometriosis, enabling improved surgical planning and patient counselling. Fixed ovaries and USL DE on TVU may be soft markers for the need for ureterolysis. Laparoscopic ureterolysis, an advanced laparoscopic skill, is difficult to predict pre-operatively, particularly in the absence of hydroureter or hydronephrosis on pre-operative imaging. This study assessed whether transvaginal ultrasound (TVU) markers (endometrioma, Pouch of Douglas ‘POD’ obliteration, uterosacral deep endometriosis ‘USL DE’ or ovarian fixation) are significantly associated with ureterolysis in women with suspected endometriosis. Prospective multicentre study assessed the diagnostic accuracy of TVU markers including endometrioma, POD obliteration, USL DE and ovarian fixation in predicting laparoscopic ureterolysis in women with suspected endometriosis who underwent laparoscopic surgery at Liverpool and Campbelltown Hospital during 2020-21 period. N/A. 63 women with suspected endometriosis were recruited. Participants underwent a specialised TVU by an expert sonologist, followed by laparoscopic surgery within 6 months by an advanced laparoscopic surgeon, who documented the intraoperative and histopathological findings. The mean age was 35. 31/63 (49%) women with suspected endometriosis required ureterolysis, 14/31(45%) complete ureterolysis and 17/31 (55%) partial ureterolysis (for the excision of localised peritoneal endometriosis over the pelvic side wall). Of the 14 women requiring complete ureterolysis, 11/14 (Sensitivity ‘Sn’ 78.57%, accuracy ‘Ac’ 53.97%, p0.13) had fixed ovaries, 8/14 (57.14%, Ac 77.78%, p0.0042) had POD obliteration, 7/14 (Sn 50%, Ac 79.37%, p0.0052) had endometrioma and 6/14 (Sn 42.86%, Ac 74.60%, p0.0634) had USL DE on TVU. Of the 17 women requiring partial ureterolysis, 8/17 (Sn 47.05%) had fixed ovaries, 5/17 (29.41%) had USL DE, 3/17 (17.65%) had POD obliteration and 1/17 (5.88%) had endometrioma on TVU. POD obliteration and endometrioma on TVU are significantly associated with the need for ureterolysis in women undergoing laparoscopy for suspected endometriosis, enabling improved surgical planning and patient counselling. Fixed ovaries and USL DE on TVU may be soft markers for the need for ureterolysis.