OBJECTIVES: To study the use and results of cystoscopy and bladder hydrodistension in the objective assessment of patients with Bladder Pain Syndrome (BPS), in routine clinical practice. MATERIAL AND METHODS: Observational, non-interventional, national, multicenter study carried out in Functional Urology and Urodynamic Units of Spain be- longing to the IFU Group. 273 women with BPS who underwent cystoscopy at baseline as a diagnostic tool according to clinical criteria and following the routine clinical practice of each center, were studied. The pre and post hydrodistension findings and the scores of the symptom and Health-Related Quality of Life (HRQoL) questionnaires were described: BPIC-SS, PPBC, PGI-S and EQ-5D-5L. RESULTS: The mean age (SD) was 59 (14) years with a high presence of bladder symptoms: increased voiding frequency (81.7%), nocturia (74%) and urgency (60.4%). 40.7% of cystoscopies were performed under anesthesia and 73.7% uses a standard rigid cystoscope. Hunner lesions were observed in 9.9% of the patients, hypervascularizations (46.2%), glomerulations (23.4%), mild bleeding (6.6%) and scars (2.2%). After hydrodistension, a greater number of grade 1 and 2 lesions were observed. In 51.6% of the patients there were no changes, but in 27.5% slight changes were observed and in 11.4% moderate or severe changes. Symptom and HRQoL questionnaire scores showed no association with cystoscopy findings before and after hydrodistension. CONCLUSIONS: The value of the cystoscopic findings in the SDV has yet to be defined, although it plays a fundamental role in the differential diagnosis. In this observational study, we did not find a correlation of the cystoscopic findings with the symptoms of the patients, measured by validated questionnaires, nor with the HRQoL.