Immediate as well as early revascularization may be beneficial in patients with acute coronary syndromes (ACS) without ST elevation, but has traditionally employed as an 'ischemia-guided' strategy. A number of randomized trials (including more than 10 000 patients) and observational studies have compared routine invasive versus selective invasive treatment in patients with an acute coronary syndrome without ST elevation. Most randomized trials are limited by a high cross-over rate, whereas observational studies are limited by selection bias. Data from registries have demonstrated benefits with an invasive approach. The results from randomized trials are less clear regarding mortality reduction, although long-term survival after hospital discharge may be better after the invasive approach. In the randomized trials, there was a decreased risk of death or myocardial infarction after the invasive approach (odds ratio = 0.88, 95% confidence interval = 0.76-1.0). Despite the optimal timing of angiography and subsequent revascularization, if appropriate, angiography and revascularization should be considered in every patient admitted with an ACS without ST elevation, particularly in patients with high-risk characteristics, such as ST segment depression > 0.1 mV, accelerated angina in the prior 2 months, nitrate use in the prior week before admission and elevated troponin.