The authors report a case of fatal Daunorubicin cardiotoxicity on initial phase of therapy for Acute Myeloblastic Leukemia at cumulative doses (225 mg/mq) considered still safe from the current literature. Despite the interruption of therapy and the interventions performed in support of cardiac functionality the patient came to exitus for heart failure 24 hours after the symptoms onset. This example represents a further confirmation of the utility of a steady monitoring with specific tests for the patients undergoing Daunorubicin therapy.