Objectives: To evaluate the outcome of endoscopic injection of two different bulking agents, glutaraldehyde cross-linked collagen and dextranomer/hyaluronic acid copolymer into the urethral submucosa in female dogs with urinary incontinence caused by urethral sphincter mechanism incompetence. Materials and MethOds: Retrospective review of records and follow-up communication with owners of dogs that received an endoscopically guided urethral bulking procedure. In each dog, either crosslinked collagen (2007 to 2011) or dextranomer/hyaluronic acid copolymer (2012 to 2015) was used.At least three injections were made in a circular arrangement in the midurethral region until the urethral lumen was closed.results: Complete questionnaires were available from 50 of 100 pet owners. The mean interval between the treatment and interview was 67 (range: 57 to 114) months in the cross-linked collagen group and 19 (range: 2 to 48) months in the dextranomer/hyaluronic acid copolymer group.The mean duration of continence was 45•8 months (range: 12 to 84 months) in the cross-linked collagen group and 20•5 months (range: 12 to 48 months) in the dextranomer/hyaluronic acid copolymer group. The success rate at 6 months or more after the procedure was 71% after the injection of cross-linked collagen and 58% after injection of dextranomer/hyaluronic acid copolymer. One minor complication (transient haematuria) occurred in one dog. There were no major complications.clinical significance: Urethral injection of dextranomer/hyaluronic acid copolymer in bitches with urethral sphincter mechanism incompetence is a useful alternative to cross-linked collagen injection, which is no longer available in the European market. Dextranomer/hyaluronic acid copolymer injection is a minimally invasive alternative to surgical procedures and has a low complication rate.