A chronic alcoholic who had casual contact with dogs developed subacute tricuspid endocarditis caused by the unusual gram-negative bacillus dysgonic fermenter type 2 (DF-2). Despite recurrent pulmonary emboli, the patient had an apparent successful response to 6 weeks of penicillin therapy. Two weeks after discharge, he experienced congestive heart failure necessitating tricuspid valvulectomy. No evidence of active infection was found in tissue removed at surgery. Despite the achievement of a bacteriologic cure, surgery for residual valve damage is not uncommon in endocarditis, regardless of the microbial etiology. In this case, alcoholism was the only risk factor predisposing to infection presumably contracted from exposure to dogs.