Effectiveness of screening for homelessness in a large healthcare system was evaluated in terms of successfully referring and connecting patients with appropriate prevention or intervention services. Screening and healthcare services data from nearly 6 million U.S. military veterans were analyzed. Veterans either screened positive for current or risk of housing instability, or negative for both. Current living situation was used to validate results of screening. Administrative evidence for homelessness-related services was significantly higher among positive-screen veterans who accepted a referral for services compared to those who declined. Screening for current or risk of homelessness led to earlier identification, which led to earlier and more extensive service engagement.