Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic pelvic pain (CPP) syndrome that is frequently seen in female patients. Since its molecular mechanism and etiopathogenesis are not clearly elucidated, its treatment options are limited. Phosphodiesterase-5 (PDE-5) inhibitors act on nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) and are an effective treatment option in some CPP syndromes. We discuss the case of a 44-year-old female patient who presented to our clinic with a two-year history of frequent urination and pain in the pelvic area. The cystoscopy of the patient, who did not benefit from first- and second-line treatments, was normal. With the diagnosis of IC/PBS, she was started on tadalafil (oral) 5 mg/day. At the end of a total of 12 months of follow-up, it was observed that the patient's symptoms significantly regressed.