Interstitial cystitis/bladder pain syndrome (IC/BPS) is estimated to affect 3.3 to 7.9 million women aged 18 years and older in the United States. The American Urological Association (AUA) defines IC/BPS as an unpleasant sensation (pain, pressure, discomfort) perceived to be related to the urinary bladder, associated with lower urinary tract symptoms of more than six weeks duration, in the absence of infection or other identifiable causes. IC/BPS significantly impacts quality of life, with the individual domains of sexual function, anxiety and depression, sleep quality and work productivity being specifically affected. Significant sexual dysfunction in women with IC/BPS has been consistently demonstrated across multiple international studies, with a prevalence ranging from 68% to 91%. In fact, among all patients with lower urinary tract symptoms, patients with a diagnosis of IC/BPS had the highest levels of impaired sexual function, mostly due to dyspareunia. Recommended treatments for IC/BPS include dietary and behavioral modifications, oral medications, bladder instillations, bladder hydrodistension, intradetrusor injection of onabotulinumtoxinA and major surgery. Scant research exists on how treating IC/BPS affects sexual function. We are conducting a prospective cohort study to assess for improvement in sexual function following intravesical onabotulinumtoxinA injection versus conservative management for IC/BPS. The study will consist of three groups: intradetrusor onabotulinumtoxinA injection, conservative management and age-matched, healthy controls. All patients aged 18 years and older presenting to the Walter Reed National Military Medical Center (WRNMMC) Urogynecology clinic who are given a diagnosis of IC/BPS and have an O'Leary Sant index questionnaire scoring 13 or greater will be eligible for the study. The primary study outcome is change in the pre- and 12-week post-treatment Female Sexual Function Index (FSFI). The secondary outcomes will include changes in the pre- and post-treatment O'Leary Sant index, Patient Global Impression of Improvement (PGI-I), Patient Global Impression of Severity (PGI-S), Pelvic Organ Prolapse/Incontinence Sexual Questionnaire, IUGA-Revised (PISQ-IR), Visual analog pain scale and 24-hour bladder diary (number of daily voids, number of nightly voids, incontinence episode). Adverse events will be monitored, including urinary tract infection or need for urinary catheterization due to urinary retention within 12 weeks of start of treatment. The age-matched, healthy control group will complete only one set of questionnaires to serve as a baseline comparison to the IC/BPS groups. For between-groups comparisons, a sample size of 49 per group will have 80% power to detect a clinically important difference of 4 points if the standard deviation is 7 points, assuming a 5% two-sided significance level. We will therefore recruit 55 subjects per group to allow for approximately 10% attrition between the pre- and post-treatment assessments. This study will be powered to detect a difference between treatments groups, which has not yet been reported in the literature.