Background There is wide variation in the use of radial over femoral access for patients with ACS. This study evaluates the factors associated with the selection of radial versus femoral angiography in Australia and New Zealand and the effect of access site on clinical events in acute coronary syndrome (ACS) patients. Methods An analysis of the SNAPSHOT ACS audit was conducted during May 2012 across 286 hospitals in Australia and New Zealand. Data collected included baseline patient characteristics, hospital site details, treatment received, clinical events in-hospital and mortality at 18 months. Univariate and multivariable analyses were performed. Results Of the 1621 patients undergoing coronary angiography, access was through the femoral artery in 1043 (63%), and the radial in 578 (36%) patients. Radial access dominated in New Zealand (241 out of 327, 73.7%), compared to Australia (337 out of 1293, 26.1%, p=<0.001), with interstate variation (6% to 54%, p=<0.001). Independent predictors of access site included country of admission (Odds of radial, Aus v NZ OR 0.14, 95% CI 0.08-0.24, p=<0.0001), prior CABG surgery (OR 0.16, 95% CI 0.09-0.31, p=<0.0001), high GRACE score (90th decile) (OR 0.44, 95% CI 0.21-0.91, p=0.026) and admission to a centre with high annual PCI volume (>209 cases per year) (OR 1.86, 95% CI 1.06-3.26, p=0.03). After adjustment, there was no difference in clinical events in-hospital or mortality at 18 months Conclusion Coronary angiography in New Zealand rather than Australia is the strongest predictor of radial access in ACS patients. There was no difference in outcomes according to access site in this population based cohort study.