['Aneurysm rupture is a major cause of morbidity and mortality, and evidence suggests shared risk for both abdominal aortic aneurysms (AAAs) and intracranial aneurysms (IAs). We hypothesized that screening for AAA in patients with known IA is cost-effective.', 'We used a decision tree model to compare costs and outcomes of AAA screening vs no screening in a hypothetical cohort of patients with IA. We measured expected outcomes using quality-adjusted life-years (QALYs) and the incremental cost-effectiveness ratio (ICER). We performed a Monte Carlo simulation and additional sensitivity analyses to assess the effects of ranging base case variables on model outcomes and identified thresholds where a decision alternative dominated the model (both less expensive and more effective than the alternative).', 'In our base case analysis, screening for AAA provided an additional 0.17 QALY (2.5-97.5 percentile: 0.11-0.27 QALY) at a saving of $201 (2.5-97.5 percentile: $-127 to $896). This yielded an ICER of $-1150/QALY (2.5-97.5 percentile: $-4299 to $6374/QALY), that is, screening saves $1150 per QALY gained.'] Is screening individuals with intracranial aneurysms for abdominal aortic aneurysms cost-effective based on estimated coprevalence?