Purpose: To identify risk factors for mortality in patients who developed mediastinitis post cardiac surgery via sternotomy.Methods: Retrospective study conducted in the cardiothoracic surgery department of HMPIT between January 1, 2010 and December 31, 2019. Mediastinitis was defined as a deep infection of the surgical site, requiring revision surgery with positive bacteriological samples, or a macroscopic aspect of infection.Mortality risk factors were sought from data relating to the patient, the initial surgery, the post-CEC operative follow-up, and the pre-, per- and postoperative management of revision surgery.Results: 55 patients were included. The mortality rate in these patients was 30.9%.The risk factors incriminated in the multivariate analysis were age over 60 years and admission in a critical condition, in contrast to a preserved LVEF, which was a protective factor.The microorganisms most frequently identified in bacteriological cultures were staphylococci, mainly aureus.