Background: The aim of the study was to compare healing (assessed by optical coherence tomography [OCT]) of biolimus A9 (BES) and everolimus drug-eluting stents (EES) at 9-month follow-up in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (pPCI). Nine-month clinical and angiographic data were also compared in both groups as well as clinical data at 5 years of follow-up.Methods: A total of 201 patients with STEMI were enrolled in the study and randomized either to pPCI with BES or EES implantation. All patients were scheduled for 9 months of angiographic and OCT follow-up.Results: The rate of major adverse cardiovascular events (MACE) was comparable at 9 months in both groups (5% in BES vs. 6% in the EES group; p = 0.87). Angiographic data were also comparable between both groups. The main finding at 9-month OCT analysis was the greatly reduced extent of mean neointimal area at the cost of a higher proportion of uncovered struts in the BES group (1.3 mm2 vs. 0.9 mm2; p = 0.0001 and 15.9% vs. 7.0%; p = 0.0001, respectively). At 5 years of clinical follow-up the rate of MACE was comparable between both groups (16.8% vs. 14.0%, p = 0.74).Conclusions: The study demonstrates a very low rate of MACE and good 9-month stent strut coverage of second-generation BES and EES in patients with STEMI. BES showed greatly reduced extent of mean neointimal hyperplasia area at the cost of a higher proportion of uncovered struts when compared to EES. The rate of MACE was low and comparable in both groups at 5 years. (Cardiol J 2023; 30, 6: 921-928)