Purpose: To estimate the cost-utility of elective EVAR compared to OSR for treating non-ruptured AAAs using information from the literature and from a prospective observational study. Methods: The cost-effectiveness of EVAR for the treatment of AAA was evaluated using a 1 year decision analytic model. Data obtained from a systematic review of the literature was used to estimate key model parameters. Information on clinical outcomes, costs and health-related quality of life were derived from the prospective study. A deterministic sensitivity analysis was conducted to assess the impact of methodological and modeling uncertainty. A probabilistic sensitivity analysis was used for parameter uncertainty. Results: The systematic literature review identified 4 randomized controlled trials and 55 observational comparative studies and suggested that the technical and clinical success rates were lower for EVAR patients; however, EVAR treated patients tended to have a higher surgical risk than OSR trial patients. Results from the prospective study demonstrated similar success rates for both OSR and EVAR (primary technical success of 100% for both groups) and much lower post-operative complication rates than compared to the published literature. The incremental cost-utility ratio, based on success and complication rates from the literature, suggests EVAR cost $160,176/QALY compared to OSR. However, results from the prospective study suggest that EVAR costs only $59,485/QALY in all AAA patients and dominates OSR in high surgical risk patients (i.e. expected cost per patient: -$9,417; expected QALYs: +0.066). Using EVAR in high risk patients only is estimated to save approximately $6 million for 2006/2007 (based on 635 EVAR cases/year). Conclusions: The predominance in the literature of non-randomized trials comparing EVAR and OSR highlights the importance of adjusting for baseline imbalances in patient risk. Using results from literature reviews of non-randomized trials for input into an economic model can be misleading. Based on these results (i.e. observation study), EVAR has been changed from an uninsured to insured service (fee code introduced). Several vascular programs in the province are being geared-up/restructures for EVAR.