A case of a 32-year-old nulligravida who underwent a carbon dioxide laser-laparoscopy for endometriosis is reported. Ureteral injury was complicated by a postoperative ‘urinoma’. Injury occurred despite utilizing the hydrodissection technique destined to create a bed of water beneath the peritoneum to prevent laser beam penetration to adjacent normal tissue. This case illustrates that the hydrodissection technique may be less effective in the presence of severe endometriotic adhesions and fibrosis.