The aim of the present study was to evaluate the impact of interhospital delay on mortality in 616 patients with ST-segment elevation myocardial infarction transferred for primary angioplasty to our hospital. Longer interhospital delay was associated with impaired perfusion, larger infarct size, and higher 1-year mortality (adjusted RR 1.5, 95% confidence interval 1.07 to 2.12; p = 0.019). These results suggest that in patients with ST-segment elevation myocardial infarction transferred for primary angioplasty, all efforts should be made to reduce time to treatment.