Background:Prior research has explored the patterns and dynamics of homelessness; such an understanding is necessary to improve policy and programmatic responses and prevent new episodes of housing instability.Objectives:The objectives of this study are to identify correlates of veterans' transitions into housing instability and inform initiatives aimed to address their needs, with a focus on how to prevent new episodes of housing instability.Methods:The cohort for this study includes 4,633,069 veterans who responded to the Veterans Health Administration's universal screen for housing instability at least twice between October 1, 2012, and September 30, 2016; 1.2% reported recent housing instability and 98.8% reported ongoing housing stability. The χ2or Fisher exact tests, as appropriate, compared veterans' characteristics by housing status. A multivariate logistic regression identified independent risk factors associated with recent housing instability, controlling for sociodemographic, military service, diagnostic, and health services use variables.Results:Sociodemographic and health services use variables increased veterans' odds of transitioning into housing instability. The diagnoses with the greatest effect sizes were drug use disorder (adjusted odds ratio=1.50, 95% confidence interval: 1.45-1.55) and opioid use disorder, which was associated with a >2-fold increase in the odds of experiencing recent housing instability (adjusted odds ratio=2.22, 95% confidence interval: 2.04-2.41).Conclusions:The present study provides evidence to inform existing and future interventions to prevent new episodes of housing instability. Veterans with opioid use disorder were at greatest risk of becoming unstably housed; increasing access to medication-assisted treatment in homeless-focused services is needed.