Bartonella quintana is a recently recognized cause of culture-negative left-sided endocarditis. We report a case of isolated tricuspid endocarditis caused by B. quintana in a 65-year-old alcoholic man, who also had immune-complex glomerulonephritis. B. quintana was established as the cause of the endocarditis based on serological tests and on failure of extensive efforts to isolate an alternative organism. The patient improved gradually on antibiotic therapy and did not require surgery. To our knowledge, this is the first report of isolated right-sided endocarditis caused by B. quintana. Although uncommon, Bartonella should be considered in patients with isolated right-sided culture-negative endocarditis.