Abstract Aims To assess low-density lipoprotein cholesterol (LDL-C) treatment target attainment among myocardial infarction (MI) patients according to the European Society of Cardiology (ESC)/European Atherosclerosis Society (EAS) dyslipidaemia guidelines from 2011 (LDL-C < 1.8 mmol/L or ≥50% LDL-C reduction) and 2016 (LDL-C < 1.8 mmol/L and ≥50% LDL-C reduction). Methods and results Using nationwide registers, we identified 44 890 patients aged 21–74 admitted for MI, 2013–17. We included those attending follow-up visits at 6–10 weeks (n = 25 466) and 12–14 months (n = 17 117) after the event. Most patients received high-intensity statin monotherapy [84.3% (6–10 weeks) and 69.0% (12–14 months)] or statins with ezetimibe (2.7% and 10.2%). The proportion of patients attaining the 2011 LDL-C target was 63.8% (6–10 weeks) and 63.5% (12–14 months). The corresponding numbers for the 2016 LDL-C target were 31.6% (6–10 weeks) and 31.5% (12–14 months). At the 6- to 10-week follow-up, 37% of those not attaining the 2011 LDL-C target and 48% of those not attaining the 2016 target had an LDL-C level that was ≥0.5 mmol/L from the target. When comparing LDL-C measurements performed before vs. after the release of the 2016 guidelines, attainment of the 2016 LDL-C target increased from 30.2% to 35.0% (6–10 weeks) and from 27.6% to 37.6% (12–14 months). Conclusion In a nationwide register, one out of three patients with a recent MI had not attained the LDL-C target of the 2011 ESC/EAS guidelines and two out of three patients had not attained the LDL-C target of the 2016 guidelines.