Dual antiplatelet therapy (DAPT) is currently the standard of care after percutaneous coronary intervention (PCI). Recent studies suggest that reducing DAPT to 1-3 months followed by an aspirin-free single antiplatelet therapy (SAPT) strategy with a potent P2Y12 inhibitor is safe and associated with less bleeding. However, to date, no randomised trial has tested the impact of initiating SAPT immediately after PCI, particularly in patients with acute coronary syndromes (ACS). NEOMINDSET is a multicentre, randomised, open-label trial with a blinded outcome assessment designed to compare SAPT versus DAPT in 3,400 ACS patients undergoing PCI with the latest-generation drug-eluting stents (DES). After successful PCI and up to 4 days following hospital admission, patients are randomised to receive SAPT with a potent P2Y12 inhibitor (ticagrelor or prasugrel) or DAPT (aspirin plus a potent P2Y12 inhibitor) for 12 months. Aspirin is discontinued immediately after randomisation in the SAPT group. The choice between ticagrelor and prasugrel is at the investigator's discretion. The primary hypothesis is that SAPT will be non-inferior to DAPT with respect to the composite endpoint of all-cause mortality, stroke, myocardial infarction or urgent target vessel revascularisation, but superior to DAPT on rates of bleeding defined by Bleeding Academic Research Consortium 2, 3 or 5 criteria. NEOMINDSET is the first study that is specifically designed to test SAPT versus DAPT immediately following PCI with DES in ACS patients. This trial will provide important insights on the efficacy and safety of withdrawing aspirin in the early phase of ACS. (ClinicalTrials.gov: NCT04360720).