Abstract Background Despite its high prevalence in patients with coronary artery disease (CAD), the association between sleep disordered breathing (SDB) and in-hospital prognosis is not well determined. Purpose We aimed to study in-hospital prognosis depending on the presence of SDB in patient hospitalized for acute myocardial infarction (AMI). Methods We prospectively enrolled a subset of patients hospitalized for AMI of the French Cohort of Myocardial Infarction Evaluation (FRENCHIE) registry included from January 2019 and December 2022 in the 16 AMI-Sleep-trained centers. Baseline and in-hospital information were collected through the FRENCHIE registry. A simplified polygraphy through ApneaLink Air+ was performed overnight during the initial hospitalization before discharge. Data were scored in centralized manner at a single center where trained physicians ascertained SDB severity based on Apnea-Hypopnea index (AHI). SDB screening was considered as positive for patients who have at least moderate SDB, defined by an AHI≥15/h. Results Among 1752 patients, 955 (54.5 [52.1;56.9] %) had at least moderate SDB. Compared with patients without SDB, SDB patients have major cardiac impairment including more 3-vessel CAD (26.8% vs 20.8%) and a lower admission left ventricular ejection fraction (52.2% vs 50.4%) associated with a higher use of non-invasive ventilation (3.8% vs 1.6% in non-SDB patients). SDB patients had also more in-hospital complications in particular more transfer to hospital intensive care (0.1% vs 0.9%) and an increased length of stay (4.8 vs 5.9 days). Conclusion More than half of the patients hospitalized for AMI had at least moderate SDB and presence of SDB was associated with more in-hospital morbidity. SDB screening should be considered to identify high risk sub-group of AMI patients.