Abstract: BACKGROUND: We used the largest integrated US health care system, the Veterans Health Administration (VHA), to establish a robust resource for demographic, longitudinal outcome, and predictive modeling studies in autosomal dominant polycystic kidney disease (ADPKD). METHODS: We built the ADPKD cohort by extracting the relevant electronic health record (EHR) data from nationwide VHA database (years 1999-2020). RESULTS: We identified 12,217 patients diagnosed with ADPKD. By the end of the 20-year study period, 5,342 ADPKD patients were deceased, 1,583 were alive but reached end-stage kidney disease (ESKD), and 4,827 remained alive without ESKD. Most demographic characteristics of this ADPKD cohort resemble the total U.S. veteran population. For example, 94% were males, 45% age 65 years or older, 85% non-Hispanic, 66% white; however, 19% were Black/African Americans (vs. 12% in the general veteran population; a relevant enrichment after considering age and sex distributions between races). The comorbidities overrepresented in the ADPKD cohort include hypertension (89% vs. 50%), diabetes (32% vs. 22%), depression (40% vs. 10%), chronic obstructive pulmonary disease (30% vs 6%), and congestive heart failure (21% vs 1%). In contrast, obesity was under-represented in veterans with ADPKD (30% vs 41%). CONCLUSIONS: We established a large EMR-based cohort of ADPKD veterans. Here we provide initial analysis of its demographic, comorbidity and key laboratory data.