Although rectovaginal fistula is a rare complication of rectal cancer surgery, it is usually difficult to cure with conservative treatment, and patients generally need surgical intervention. A woman in her 70s underwent laparoscopic low anterior resection with right lateral lymph node dissection for rectal cancer. On postoperative day(POD)6, she had an anastomotic leakage and received conservative treatment. On POD 9, she underwent emergent laparotomy for urinary peritonitis as well as ileostomy and ureteral stenting. On POD 21, the rectovaginal fistula was confirmed with lower gastrointestinal tract fluoroscopic examination. The patient received conservative therapy for the rectovaginal fistula with estriol vaginal tablets and vaginal lavage for 2 weeks. Subsequently, the fistula was completely cured. After continuation of the estriol vaginal tablets for 4 weeks, the rectovaginal fistula has not recurred at the most recent follow-up.