Background Unlike neighboring countries, the Netherlands does not have a national acute coronary syndrome (ACS) registry to evaluate quality of care. Objective We conducted a pilot registry in two hospitals to assess the prescription of guideline-recommended therapies in Dutch patients with ACS. Methods We included all consecutive patients with ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) (n = 1309) admitted to two Dutch percutaneous coronary intervention centers between March 2015 and February 2016. We collected follow-up medication use and reasons for discontinuation at discharge and 1, 6, and 12 months post-discharge. We assessed the use of optimal medical therapy (OMT), defined as the combined prescription of aspirin, P2Y12 inhibitors, statins, beta-blockers, and angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers. Results OMT prescription was 43.2% at discharge, 60.1% at 1 month, and 28.7% at 12 months. At 1 month, OMT prescription was significantly lower in patients with NSTEMI (51.8 vs. 65.7% for STEMI;p<0.001). OMT prescription was lower in women (6 months: 55.4 vs. 62.0%,p= 0.036) and in elderly patients. Conclusion In this pilot study that aimed to extend a national Dutch ACS registry to patients with STEMI and NSTEMI, OMT prescription was comparable to that in other local registries, was lower in women and patients with NSTEMI, and decreased with increasing age.