OBJECTIVES: Major bleeding in acute coronary syndrome (ACS) patients has a significant impact on clinical outcomes. The economic costs associated with these events have not been assessed. This study was undertaken to estimate the costs associated with manage major bleeds in ACS patients in the hospital setting METHODS: A retrospective chart review was undertaken in a French hospital to identify ACS patients with the following bleeding events: intracranial haemorrhage (ICH), retroperitoneal (RP) gastrointestinal (GI), puncture site or excessive surgical bleeds (PSB), blood transfusion requiring 2 or more units, or decrease in Hb > 3g/dL (DHb). Patient age, reason for admission, extended length of stay (LOS) attributed to the bleed, ward type, and resources to manage the bleed were collected. RESULTS: 48 cases were analysed, 52% were males, with an average age of 72.5 years. The reasons for hospital admission were 39.6% non ST-segment Elevation Myocardial Infarction (NSTEMI), 43.8% ST-segment Elevation MI (STEMI) and 10.4% unstable angina (UA). The distribution of hemorrhagic events were 40.4% DHb, 27.7% transfusions, 21% PSB, 8.5% GI and 2.1% RP bleeds. The mean length of stay (LOS) was 8.5 days across all patients. Extended 6.5 day mean LOS (76% of total stay) was found for 20 patients. The number of extra days varied by type of bleed. 80% of PSB patients had extended stays compared to 50% of GI bleed, 38% of transfusion and 21% DHb patients. Ultrasound was the most common additional procedure followed by endoscopy. Applying unit costs from France for procedures, transfusions, and extended LOS resulted in additional costs of €1709 for DHb, €3245 for transfusions, €2116 for GI, €4091 for RT and €6585 for PSB. CONCLUSION: Hospitalised ACS patients with bleeding complications have increased mean resource use and 41% have extended LOS leading to an estimated additional average €3185 for the hospital stay.