Herein, we aimed to review, report, and discuss the role of cystoscopy and clinical phenotyping in interstitial cystitis/bladder pain syndrome (IC/BPS). For this purpose; a comprehensive nonsystematic review of the relevant literature was conducted. We reviewed articles published in English and indexed in the PubMed, Embase, and Google Scholar databases. Original manuscripts, review articles, case series, and case reports were taken into consideration. Data regarding the indications for, technique, and possible findings of cystoscopy with hydrodistension (HD) and biopsy, as well as clinical implications of cystoscopic information and the concept and use of clinical phenotyping within the context of IC/BPS were extracted and discussed. IC/BPS is diagnosed based on symptomatic assessment and exclusion of confusable diseases. There is no universal agreement upon the evaluation and diagnostic algorithm of IC/BPS. The majority of the guidelines recommend cystoscopy with HD and biopsy as a diagnostic prerequisite. Various different techniques have been described for cystoscopy with HD. General or epidural anesthesia is more commonly preferred and advocated while assessing endoscopic alterations in patients suspected of having IC/BPS. Cystoscopy with HD and biopsy enables more objective exclusion of confusable diseases. It also provides the basis of the European Society for the Study of Interstitial Cystitis classification. Patients with IC/BPS who demonstrate positive cystoscopic (glomerulations and/or Hunner lesion) and histologic findings have a more severe symptomatology and may benefit from lesion-targeted endoscopic treatments. Clinical phenotyping has been implemented for IC/BPS and may be used for individualized assessment and treatment.