AAA is a prevalent health condition affecting up to 14% of males and 6% of females. Untreated AAAs is a serious health concern due to significant risks of rupture and death. OBJECTIVES: Estimate the cost-utility of elective EVAR compared to OSR for treating non-ruptured AAAs. METHODS: A decision analytic model was constructed to represent the long term cost-effectiveness of AAA. A systematic review of the literature was conducted for estimates of key model parameters (including technical and clinical success rates, complication rates, conversion rates and mortality). The review of the literature was supplemented with a prospective follow-up of patients from a large tertiary hospital for information on costs and health-related quality of life. Cost-utility was assessed over a one-year period. Deterministic sensitivity analyses were used to assess the impact of methodological and modeling uncertainty and probabilistic sensitivity analyses was used for parameter uncertainty. RESULTS: The 59 comparative studies identified from the literature suggest the technical and clinical success rates are lower for EVAR patients, however, EVAR treated patients tended to be older, male, and had larger aneurysms, increased surgical risk, and more comorbidities than OSR trial patients. Our prospective study showed success rates for both OSR and EVAR are very high and complication rates are much lower than reported in the published literature. Cost-utility based on success and complication rates from the literature suggests EVAR cost $160,176 per QALY compared to OSR. However, results from our prospective study suggest EVAR costs only $59,485 per QALY in all AAA patients and may even dominate OSR in high surgical risk patients. CONCLUSIONS: Using results from literature reviews of non-randomized trials for input into an economic model can be misleading. The predominance of non-randomized trials comparing EVAR and OSR highlights the importance of adjusting for baseline imbalances in patient risk.