Statin pretreatment has been reported to have a cardioprotective effect in patients undergoing elective or urgent percutaneous coronary intervention (PCI). However, data on patients with ST-elevation myocardial infarction (STEMI) undergoing primary PCI are still controversial. We prospectively evaluated the effect of long-term statin therapy on infarct size (IS), myocardial salvage index (MSI), and microvascular obstruction (MVO) in consecutive patients with STEMI who underwent primary PCI. Two-hundred thirty patients with STEMI (mean age 61 ± 11 years, 183 men) who underwent primary PCI were evaluated with cardiac magnetic resonance (CMR) imaging during hospitalization (median 4 days after primary PCI). In all patients, we measured peak troponin I level, whereas IS, MSI, and MVO were determined by CMR. Fifty patients (22%) were on long-term statin therapy and showed a significantly lower troponin I peak value compared to patients without previous statins (54 ± 47 vs 88 ± 106 ng/ml; p = 0.02). At CMR evaluation, IS related to the index event was significantly smaller (12.5 ± 11.5 vs 18.5 ± 18.5 g, p = 0.05), and MSI was higher (0.68 ± 0.25 vs 0.52 ± 0.30; p