The optimal timing of invasive diagnosis and therapy in patients with non-ST-elevation myocardial infarction (NSTEMI) is still a matter of debate. The European Society of Cardiology recommends invasive diagnosis evaluation and revascularization for practically all patients with NSTEMI within 72 h. High risk and very high risk patients should be evaluated invasively with coronary angiography within 24 h or 2 h, respectively. The risk of the individual patient should be stratified by means of the Global Registry of Acute Coronary Events (GRACE) risk score. The recommendations and guidelines are based on the results of several randomized, controlled trials and are in accordance with other retrospective studies. However, observational studies indicate that in real life many high risk patients are not evaluated invasively by coronary angiography as timely as recommended.