Infectious endocarditis is a rare pathology whose mortality is high and whose diagnosis is still difficult by the usual clinical, biological and ultrasound tools. We report the case of a patient, drug addict, suffering from an infectious endocarditis of the aortic valve at Streptococcus agalactiae. This germ is rarely at the origin of cardiac infection but it is responsible for quickly destructive lesion by its pathophysiological mechanisms. In this case, the infection unfortunately caused the death of the patient.