STUDY OBJECTIVE: To estimate the prevalence of bladder-origin pain, intraperitoneal pathology, and vulvar pain in patients undergoing laparoscopy for chronic pelvic pain (CPP). DESIGN: Prospective, observational one-site (Canadian Task Force classification II-2). SETTING: Referral gynecology specialty private practice. PARTICIPANTS: Sixty-four patients undergoing laparoscopy for CPP were prospectively assessed to establish the source of their CPP over a 12-month period. INTERVENTIONS: All patients received an intravesical potassium sensitivity test (PST), cystoscopy with double-fill hydrodistension, a physical examination for vulvar pain, and laparoscopy to assess the presence of peritoneal pathology. The validated pelvic pain/urgency/frequency (PUF) screening questionnaire was given to all patients to assess symptoms. MEASUREMENTS AND MAIN RESULTS: Forty-four patients (69%) were found to have a positive PST indicating pain of bladder origin due to bladder epithelial dysfunction. Cystoscopic findings diagnosed only seven cases of classic interstitial cystitis (11%). Laparoscopic findings revealed biopsy-proven endometriosis in 28% and adhesions in 64%. Vulvar pain was diagnosed on examination in 20%. Assessment of intraperitoneal pathology and bladder-origin pain accurately diagnosed 95% of patients. There was no statistical difference in the prevalence of endometriosis, adhesions, or vulvar pain when groups were stratified to PST-positive or -negative groups. Bladder pain, peritoneal pathology, and vulvar pain are independent risk factors of CPP although a trend of severity was noted in patients who had worse symptoms (increased voids per day, urgency, pain, and PUF scores). Patients with increased symptoms had a higher likelihood of having pain from bladder epithelial damage and intraperitoneal pathology. CONCLUSIONS: The etiology of CPP may arise from multiple sites in the pelvis including the bladder, pelvic peritoneum, and vulva. This study demonstrated that in a group of women undergoing a comprehensive work-up for CPP, the bladder was the predominant pain generator. A work-up for CPP should include an assessment of bladder epithelial function and an assessment for intraperitoneal pathology. (c) 2005 AAGL. All rights reserved.