The aim of the study is to determine the influence of anemia on the duration of hospital stay in patients with acute coronary syndrome. A retrospective study was conducted in all coronary patients admitted to the cardiology service of Ibn-Rochd Hospital in Casablanca between January and April 2018. Anemia was defined as Hb <13g/dL in men and <12g/dL in women (WHO definition). Biological markers were collected at admission. The patients were followed for 1 month. Among the 215 patients included, there were 141men and 74women, the average age was 59.3years. Seventy-seven patients had ST-segment elevation coronary syndrome, 44patients had ST-segment elevation-related coronary artery disease, and 94had myocardial infarction. A total pf 121patients had 56.27% anemia. Anemia was more common in women. Cardiovascular risk factors, subclinical atherosclerosis, lower extremity arteritis, and inflammatory syndrome were more common in anemic patients. The latter presented more complications during their hospitalization. Mean hospital stay in anemic patients was longer (11.8 vs. 6.2 days, P=0.03). Anemia is common in patients with ACS and is associated with a longer duration of hospitalization exposing the patient to the risk of care-related complications.