Objective: To characterize Urologic Chronic Pelvic Pain Syndrome (UCPPS) pain and urinary symptom trajectories with up to 9 years of follow-up and evaluate whether initial 1-year trajectories are associated with longer-term changes. Materials and Methods: Data were analyzed from the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Network's prospective observational protocols including the Epidemiology and Phenotyping Study (EPS; baseline to Year 1), EPS Extension (EXT; Years 1-5), and Symptom Patterns Study (SPS: 3-year study; Years 3-9). Adults with Interstitial Cystitis/Bladder Pain Syndrome or Chronic Prostatitis/Chronic Pelvic Pain Syndrome provided patient-reported assessments biweekly (EPS), every 4 months (EXT), or quarterly (SPS). Primary outcomes were composite pain (0-28) and urinary (0-25) severity scores. Multi-phase mixed effects models estimated outcomes over time, adjusted for baseline severity and stratified by EPS symptom trajectory. Results: 163 participants (52% women; mean ± SD age 46.4 ± 16.1 years) completed EPS and enrolled in EXT; 67 also enrolled in SPS. Median follow-up was 4.6 years (range 1.3-9.0). After 1 year: 27.6%, 44.8% and 27.6% and 27.0%, 38.0% and 35.0% were improved, stable or worse in pain and urinary symptom severity, respectively. On average, pain and urinary symptom scores did not change further during EXT and SPS periods. Conclusions: Women and men with UCPPS showed remarkable stability in pain and urinary symptom severity for up to 9 years, irrespective of their initial symptom trajectory, suggesting UCPPS is a chronic condition with stable symptoms over multiple years of follow-up.