Objective: To examine how often urologic chronic pelvic pain syndrome (UCPPS) patients progressed from Pelvic Pain Only at baseline to Widespread Pain, or vice versa, during 1-year longitudinal follow-up. Methods: Men and women with UCPPS enrolled in the MAPP-I Epidemiology and Phenotyping Study completed a self-report body map to indicate their locations of pain every 2 months over 12 months. Patients were categorized at each assessment into one of three pain phenotypes: (1) Pelvic Pain Only, (2) an Intermediate group, (3) Widespread Pain. Only patients who completed 3 or more follow-ups were included in this longitudinal analysis. The primary outcome measure was pain classification at the majority (≥60%) of follow-up assessments. Longitudinal trends of somatic symptom burden were also assessed. Results: Among the 93 UCPPS participants with Pelvic Pain Only at baseline, only 2% (n = 2) showed a Widespread Pain phenotype for the majority of assessments over 12 months. Among the 121 participants who had Widespread Pain at baseline, 6% (n = 7) demonstrated Pelvic Pain Only for the majority of assessments over 12 months. Over half of participants (≥53%) stayed in their baseline phenotypic group. Somatic symptom burden remained stable over 12 months for each of the groups with high intra-class correlation coefficient (0.67 to 0.82). Conclusion: It was uncommon for UCPPS patients to progress from Pelvic Pain Only to Widespread Pain, or vice versa, over 12 months. These data suggest that Pelvic Pain Only and Widespread Pain are distinct UCPPS phenotypes that are relatively stable over 12 months of follow up.