INTRODUCTION: Length of hospital stay (LHS) is an indicator of clinical effectiveness. Early hospital discharge (</=72 hours) is recommended in patients with acute coronary syndromes (ACS) at low risk of complications, but reasons for prolonged LHS poorly reported. METHODS: We collected data of ACS patients hospitalized at the Geneva University Hospitals from 1st July 2013 to 30th June 2015 and used the Zwolle index score to identify patients at low risk (</= 3 points). We assessed the proportion of eligible patients who were successfully discharged within 72 hours and the reasons for prolonged LHS. Outcomes were defined as adherence to recommended therapies, major adverse events at 30 days and patients' satisfaction using a Likert-scale patient-reported questionnaire. RESULTS: Among 370 patients with ACS, 255 (68.9%) were at low-risk of complications but only 128 (50.2%)were eligible for early discharge, because of other clinical reasons for prolonged LHS (e.g. staged coronary revascularization, cardiac monitoring) in 127 patients (49.8%). Of the latter, only 45 (35.2%) benefitted from an early discharge. Reasons for delay in discharge in the remaining 83 patients (51.2%) were mainly due to delays in additional investigations, titration of medical therapy, admission or discharge during weekends. In the early discharge group, at 30 days, only one patient (2.2%) had an adverse event (minor bleeding), 97% of patients were satisfied by the medical care. CONCLUSION: Early discharge was successfully achieved in one third of eligible ACS patients at low risk of complications and appeared sufficiently safe while being overall appreciated by the patients.