A large hematoma resulting from hemorrhagic cystitis after uncomplicated pelvic reconstruction surgery with a transvaginal mesh is rare. A 66-year-old female who underwent pelvic reconstruction with transvaginal mesh presented with acute urinary retention and hematuria on postoperative day 10. Leukocytosis, pyuria, and hematuria were noted in the emergency room. After using cystoscopy to irrigate the coagulum, there was no mesh erosion or bladder perforation on inspection. A large bladder hematoma resulting from infectious hemorrhagic cystitis was confirmed, and uropathogenic Escherichia coli was isolated. The clinical condition improved after a 1-week treatment with an indwelling Foley catheter and oral antibiotics. Careful aseptic techniques and antibiotic prophylaxis reduce bacterial contamination only for brief periods of time, and patients may still be at risk for delayed infections. The possible modalities to prevent postoperative urinary tract infection after pelvic reconstruction surgery with transvaginal mesh include shortening the indwelling Foley catheter period and administration of an additional antibiotic during catheter removal. However, the antibiotic policies for pelvic reconstruction with transvaginal mesh demand further cost analyses.