BACKGROUND: Vaginal preparation before transvaginal gynecological surgeries improves the success rate. However, there is no consensus on which agent is superior for transvaginal repair of vesicovaginal fistula (VVF). We aimed to compare irritation symptoms and antimicrobial function between sterile normal saline (SS) and 1% povidone-iodine (PI) for vaginal preparation in surgical repair of VVF. METHODS: This randomised, controlled trial was conducted on patients with VVF underwent transvaginal repair. Preoperative vaginal irrigation was randomly performed with either SS or 1% PI. The patients' self-reported symptoms questionnaires, including numerical rating scale (NRS) of pain, Indevus urgency severity scale (IUSS), and vaginal symptoms, tissue edoema degree and pathogenic microbiology were recorded. RESULTS: The study included 30 patients in the SS group and 31 patients in the PI group. After twice irrigations before surgery, compared with the PI group, the SS group had a similar count of bacterial species but a higher bacterial load ( CONCLUSIONS: SS is an effective vaginal preparation liquid for transvaginal repair of VVF with less irritation symptoms and acceptable antimicrobial function.