Study ObjectiveTo assess long-term urinary function for women having laparoscopic surgery for endometriosis. DesignInstitutional Review Board-approved nested cohort study within a larger randomized controlled trial (RCT) assessing urinary function following any benign laparoscopy for gynecological presentations SettingTwo tertiary level university-affiliated hospitals PatientsWomen with histologically confirmed endometriosis within the RCT between April 2012 and November 2019 where baseline urinary function was determined InterventionsWomen with histologically confirmed endometriosis were contacted between February and October 2020 and urinary function was re-assessed MeasurementsUrinary function was assessed using validated questionnaires across the domains of filling, voiding, incontinence and quality of life determined distant from surgery. Higher scores correlated with a greater severity of symptoms Main ResultsFrom 518/711 (72.9%) women with histologically confirmed endometriosis, 289/518 (55.8%) consented to the nested study. At a mean of 50 months (range 12-103 months) post-operatively, 35 participants (12.1%) had sought treatment for bladder symptoms and 81 participants (28.0%) reported at least one urinary tract infection (UTI) since their index surgery. There was a significant worsening of symptoms for filling, voiding, incontinence and quality of life pre-operative to post-operatively (2.27 vs 3.32, 0.93 vs 2.02, 1.06 vs 2.32, 0.83 vs 2.13 respectively, p<.001). There was no statistically significant difference in urinary questionnaire scores in participants with and without uterovesical endometriosis. There was no statistically significant difference in any parameter when comparing any rASM stage of endometriosis. Participants who had post-operative urinary retention reported a higher mean voiding score than those who did not (3.24 vs 1.94, p=.017), while participants with post-operative UTI reported a higher mean frequency score than those who did not (5.17 vs 3.24, p=.016). ConclusionThis study suggests a decline in urinary function over time following laparoscopic surgery for endometriosis, that is not dependent on severity or location of disease.