OBJECTIVE: Suicide screening followed by an intervention may identify suicidal individuals and prevent recurring self-harm, but few cost-effectiveness studies have been conducted. This study sought to determine whether the increased costs of implementing screening and intervention in hospital emergency departments (EDs) are justified by improvements in patient outcomes (decreased attempts and deaths by suicide). METHODS: The Emergency Department Safety Assessment and Follow-up Evaluation (ED-SAFE) study recruited participants in eight U.S. EDs between August 2010 and November 2013. The eight sites sequentially implemented two interventions: universal screening added to treatment as usual and universal screening plus a telephone-based intervention delivered over 12 months post-ED visit. This study calculated incremental cost-effectiveness ratios and cost-effectiveness acceptability curves to evaluate screening and suicide outcome measures and costs for the two interventions relative to treatment as usual. Costs were calculated from the provider perspective (e.g., wage and salary data and rental costs for hospital space) per patient and per site. RESULTS: Average per-patient costs to a participating ED of universal screening plus intervention were $1,063 per month, approximately $500 more than universal screening added to treatment as usual. Universal screening plus intervention was more effective in preventing suicides compared with universal screening added to treatment as usual and treatment as usual alone. CONCLUSIONS: Although the choice of universal screening plus intervention depends on the value placed on the outcome by decision makers, results suggest that implementing such suicide prevention measures can lead to significant cost savings.