PROJECT SUMMARY This is an application from the Washington University Discovery Site to continue participation in the the MAPP Research Network. The Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network was established by the NIDDK to study the etiology and treated natural history of urologic chronic pelvic pain syndrome (UCPPS), to inform better treatments and management of symptoms through improved designs of clinical trials, and to identify clinical factors and research measurements to define clinically relevant sub-groups (“phenotypes”) of these patients. The MAPP Network’s second Project Period (2014-2019) central protocol, the Trans-MAPP Symptom Patterns Study (SPS), involves integrated phenotyping of UCPPS participants at baseline and during a 36-month longitudinal, observational period using expanded measures to further refine UCPPS subgrouping, identify symptom trends, and discover associated risk factors and biological correlates to progression profiles. As of October 2018, 570 men and women with UCPPS are enrolled in the MAPP II study, and we expect to meet the recruitment goal of 600 by the end of December 2018. The current funding period ends in July 2019. We propose a three-year funding extension, through July 2022. During the three-year extension we aim to accomplish the following: Aim 1: To Obtain an Additional 12 Months of Follow-up in the MAPP-II SPS. Aim 2: To Observe Additional ATLAS Events in the MAPP-II SPS. Aim 3: To Conduct Analyses of MAPP II Data.