A case of highly invasive native valve endocarditis, occurring in a young man with a preexisting cardiac anomaly, and caused by Staphylococcus lugdunensis is described. Despite treatment with antibiotics the disease progressed with further growth of the bacterial vegetations and invasion of the myocard. The patient was successfully treated by surgery. Twenty three cases of endocarditis by S. lugdunensis have now been described. This organism is a major cause of destructive endocarditis accompanied by high mortality. As the outcome usually is more favourable in patients who underwent valve replacement surgery, rapid identification to the species level of coagulasenegative staphylococci is required. S. lugdunensis endocarditis should be treated preferably by surgical intervention.