A 58-year-old woman presented to our emergency room with cystitis-like symptoms and macroscopic hematuria. Her symptoms were improved by the administration of an antibiotic, but transabdominal ultrasonography revealed a mass in her pelvis. The pelvic magnetic resonance imaging (MRI) depicted a solid tumor in the retropubic space. The patient requested hasty surgical excision of the tumor, rather than the conservative treatment after the diagnosis by cytology and biopsy. The postoperative histopathological examination revealed nodular fasciitis. She has been followed up for 8 months without any evidence of local recurrence. Nodular fasciitis is a mesenchymal lesion of proliferated fibroblast and commonly occurs in the subcutaneous tissue of the extremities. Frequently, it resembles a sarcoma, but it is said to be a benign disorder. In the urological domain, 14 intravesical cases have been reported. To our knowledge, this is the first case of the nodular fasciitis arising in the pelvis. We report this case and discuss the literature.