UNLABELLED: The Centers for Disease Control and Prevention and U.S. Preventive Services Task Force have highlighted public screening as an essential strategy for increasing hepatitis C virus (HCV) detection in persons born between 1945 and 1965 ("baby boomers"). Because earlier HCV screening efforts have not targeted emergency department (ED) baby boomer patients, we describe early experience with integrated opt-out HCV antibody (Ab) screening of medically stable baby boomers presenting to an urban academic ED. We performed HCV Ab testing 24 hours per day and confirmed positive test results using polymerase chain reaction (PCR). The primary outcome was prevalence of unrecognized HCV infection. Among 2,325 unique HCV-unaware baby boomers, 289 (12.7%) opted out of HCV screening. We performed HCV Ab tests on 1,529 individuals, of which 170 (11.1%) were reactive. Among Ab reactive cases, follow-up PCR was performed on 150 (88.2%), of which 102 (68.0%) were confirmed RNA positive. HCV Ab reactivity was more likely in males compared to females (14.7% vs. 7.4%; P<0.001), African Americans compared to whites (13.3% vs. 8.8%; P=0.010), and underinsured/ uninsured patients compared to insured patients (16.8%/16.9% vs. 5.0%; P=0.001). Linkage-to-care service activities were recorded for 100 of the 102 confirmed cases. Overall, 54 (54%) RNA-positive individuals were successfully contacted by phone within five call-back attempts. We confirmed initial follow-up appointments for 38 (70.4%) RNA-positive individuals successfully contacted, and 21 (55.3%) individuals with confirmed appointments attended their initial visit with a liver specialist; 3 (7.9%) are awaiting an upcoming scheduled appointment. CONCLUSION: We observed high prevalence of unrecognized chronic HCV infection in this series of baby boomers presenting to the ED, highlighting the ED as an important venue for high-impact HCV screening and linkage to care.