Mortality and Morbidity conferences (MMCs) are needed for identification of the mechanisms of in hospital poor outcomes which are often considered to be related to medical errors. To determine the leading causes of death and the ethical issues raised from mortality conferences. Between January 2002 and January 2008, reports of 146 patients deceased at an hybrid surgical and interventional cardiac department were analyzed during MMCs. System failure, causes of death, ethical questions. The majority of reports presented for discussion concerned patients referred to cardiac surgery (n = 115), followed by interventional cardiology (n = 25) and medical treatment alone (n = 11). Interventions were recommended as class I in 120 cases (82%). History of renal failure (25%), peripheral artery disease (21%), diabetes (18%), cancer (16%) and respiratory disease (16%) were frequently noticed. Nosocomial infections rate was 35%. The most frequent questionable attitudes concerned preoperative strategy (58%), surgical technique (50%), monitoring (47%), reactivity (43%), drug prescription (32%), diagnostic difficulty or delay (27%) and transfer (21%). At least one transgression from normative medical practice was identified in 66 (45%) patients with a causal relation to death suggested in 33 cases (23%). Serious errors concerned 5 patients (3%) with a causal relation to death suggested in 2 cases. Ethical discussion focused on therapeutic alternatives (73%), good medical practice (44%), secondary recommendations (18%), information (12%), consent (12%), non-malfeasance (7%) and equity (6%). Participation to MMCs offers the opportunity to evidence numerous system failure. Poor outcome is multifactorial. The concept of medical errors might be redefined as questionable or transgressive attitudes which were rarely considered as the main cause of hospital death.