Bacterial endocarditis caused by Actinobacillus actinomycetemcomitans (AA) is an extremely rare disease. AA, a gram negative cocco-bacillus, normally resides in the oral cavity. It is involved mostly in local oral cavity infections, but severe systemic infections caused by it have been reported. We describe a 63-year-old man with endocarditis caused by AA which probably originated from a dental abscess. The course of the disease was complicated by acute myocardial ischemia, apparently caused by coronary artery embolism. To enable growth of this bacterium, blood cultures should be maintained for 2-3 weeks in a CO2-rich atmosphere.