OBJECTIVE: While the effectiveness of emergency departments (ED) in screening for HIV and syphilis is understood, less is known about dual screening programs. We aim to evaluate the impact of an opt-out provider-initiated HIV and syphilis program on screening, diagnosis, and linkage to care outcomes. METHODS: We performed a retrospective review of patients screened pre (2014-2017) and post (2017-2021) program implementation. Primary outcomes include HIV and syphilis screening, incidence of positive tests, and proportion of patients linked to care. Secondary outcomes included pre-exposure prophylaxis (PrEP) referral and successful linkage rates for HIV-negative syphilis-positive patients. RESULTS: Pre-implementation, 882 HIV tests were performed, of which 22 (2.49%) were new cases and 18 (81.82%) were linked to care; 754 syphilis tests were performed, of which 33 (4.38%) were active infections and 30 (90.91%) were treated. No eligible patients received PrEP referral. Post-implementation, 12,999 HIV tests were performed, of which 73 (0.56%) were new cases and 55 (75.34%) were linked to care; 10,885 syphilis tests were performed, of which 216 (1.98%) were active infections and 188 (87.04%) were treated. 25 (9.09%) eligible patients were referred for PrEP, and four (16.0%) attended their appointment. CONCLUSIONS: Post-implementation, there was a 1373.81% and 1343.63% increase in screening, and a 231.82% and 554.55% increase in positive cases of HIV and syphilis, respectively. Dual screening programs can be successfully implemented within the existing ED framework to increase screening and early detection for HIV and syphilis.