Purpose: We evaluated the effectiveness of combining behavioral therapy, pharmacologic therapy and endoscopic hydrodistension for treating painful bladder syndrome / interstitial cystitis (PBS/IC). Materials and Methods: Twenty-five patients with PBS/IC were prospectively enrolled in a pilot multimodal behavioral, pharmacologic and endoscopic treatment protocol. Behavioral modification included diet recommendations, fluid restriction to 64 oz. /day, progressive timed voiding and Kegel exercises. Oral pharmacologic therapy consisted of daily doses of macrodantin 100 mg, hydroxyzine 10-20 mg and urised 4 tablets. Patients underwent endoscopic bladder hydrodistention under anesthesia at least 2 weeks after protocol enrollment. Behavioral and pharmacological treatments were continued after the hydrodistention. O'Leary-Sant questionnaire scores were recorded before starting the protocol, after pharmacologic/behavioral therapy, 2 months post-hydrodistension, and at scheduled follow-up. Results: Eighteen patients (72%) completed the pilot multimodal treatment protocol and were followed for a mean of 10.2 months. All patients were female with a median age of 36.3 years and had mean bladder capacity under anesthesia of 836 milliliters. Mean O'Leary-Sant symptom index scores for baseline symptoms, after behavioral/pharmacologic treatment, post-hydrodistension and during follow up were 12.5, 8.6, 7.0, and 6.7 (p < 0.05). Mean O'Leary-Sant problem index scores for baseline, after behavioral/pharmacologic treatment, post-hydrodistention and during follow up were 12.7, 8.9, 6.7, and 7.7 (p < 0.05). Conclusion: Our pilot multimodal protocol of behavioral modification, pharmacologic therapy and endoscopic hydrodistention demonstrated a significant progressive improvement in PBS/IC quality of life scores, compared to a pre-treatment baseline. These results should be validated in a larger, placebo controlled trial.