Chronic nonbacterial prostatitis or chronic pelvic pain syndrome (CPPS) causes morbidity, both through symptoms and associated impairment in health-related quality of life, both of which illustrate the importance of patient-centered outcomes. Despite preliminary work by several investigators, research and clinical efforts to provide help for men afflicted with CPPS have been hampered by the absence of a widely accepted, reliable, and valid instrument to measure symptoms and quality-of-life impact. Investigators from the National Institutes of Health (NIH)-funded Chronic Prostatitis Collaborative Research Network (CPCRN) sought to remedy this problem by developing a psychometrically valid index of symptoms and quality-of-life impact in men with chronic prostatitis. This instrument, now validated in English, Spanish, German, and Korean, is known as the NIH Chronic Prostatitis Symptom Index (NIH-CPSI). It contains 13 items that are scored in 3 discrete domains: pain, urinary symptoms, and quality-of-life impact. In early studies, the NIH-CPSI has been shown to be reliable, valid, and responsive to change. Further work is needed to determine whether it performs as well in minority populations, men seeking care in nonreferral centers, and other diverse populations.