The purpose of this study was to evaluate changing trends in therapy and determinants of outcomes among patients with a renal artery aneurysm (RAA) undergoing surgical or endovascular repair in New York State (NYS). A retrospective cohort study of patients who underwent therapy for RAA in NYS from October 1, 2000, to December 31, 2006, was identified from the Statewide Planning and Research Cooperative System database. Regression models which included hospital and patient characteristics were created to identify predictors of untoward events following surgical or endovascular intervention. Over this time period 215 patients with RAA repairs were analyzed. In multivariate analysis, preoperative predictors of death included diabetes (adjusted odds ratio [OR]=57.8, 95% confidence interval [CI] 2.3-1,430.1, p=0.013), the presence of other aneurysms (adjusted OR=18.5, CI 1.5-234.4, p=0.024), and coagulopathy (adjusted OR=16.9, CI 3.4-393.1, p=0.03) but not repair type. Perioperative cardiac (adjusted OR=16.7, CI 1.4-197.1, p=0.026) and vascular device-related (adjusted OR=11.1, CI 1.003-123.0, p=0.049) complications were predictive of mortality. When patients with other aneurysms were excluded from analysis (n=153), there were no significant predictors of death. Ninety-one endovascular and 124 open surgical repairs were performed with a significant increase in the proportion of endovascular repairs performed over time (p<0.001), although since 2003 the proportion of both has been roughly equal. Diabetes (15.4% vs. 5.6%, p=0.018), chronic anemia (5.5% vs. 0.8%, p=0.04), and emergent admission (48.4% vs. 24.2%, p<0.001) were more prevalent among those with endovascular repair. Endovascular therapy was associated with a lower incidence of complications, lower median length of stay (4 vs. 7 days, p<0.001), and lower rates of discharge to skilled nursing facilities (18.9% vs. 39.2%, p=0.001). There has been an increasing number of treated RAAs in NYS since 2000, with the increase being primarily in those treated by endovascular techniques. Whether this represents a true increase in RAA incidence requiring management or an extension of indications is unknown. Outcomes after endovascular repair were better than those after conventional surgery, although whether this was due to the technique of repair itself or preprocedural selection bias cannot be determined.