Objectives: Administration of the glycoprotein IIb/IIIa inhibitor abciximab to patients with ST segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) improves outcome. Data have suggested that an intracoronary (IC) bolus might be superior to the standard intravenous (IV) administration. We have previously reported reduced short-term mortality and need for target vessel revascularization (TVR) with the IC route. We now present long-term data from our randomized trial on IC versus IV abciximab in pPCI-treated STEMI patients. Methods: A total of 355 pPCI-treated STEMI patients were randomized to either IC or IV bolus abciximab followed by a 12-hour IV infusion. Patients were followed for 1 year to observe mortality, TVR or myocardial infarction (MI) and the combination of these. Results: The two treatment arms (IV, n = 170; IC, n = 185) were similar with regard to baseline characteristics. Mortality was reduced from 10% in the IV group to 2.7% in the IC group (p = 0.004). TVR and MI were also reduced with IC administration (TVR: 14.1 vs. 7.6%, p = 0.04; MI: 11.8 vs. 5.4%, p = 0.03). Consequently, patients in the IC treatment arm had a relative risk reduction of 55% for the combined endpoint after 1 year (p = 0.002) compared to the IV treatment arm. Conclusions: In pPCI-treated STEMI patients treated with abciximab, IC bolus administration resulted in a significant reduction in mortality, TVR and MI compared to IV bolus administration.