Abiotrophia defectiva,formerly designated as the member of nutritionally variant streptococci, is a part of normal oral flora and may be a cause of culture-negative endocarditis. We report a case of infective endocarditis caused byA. defectivainvolving the mitral valve in a 12-year-old girl. She received antibiotic treatment for 8 weeks and was symptom-free 6 months after discharge. We also reviewed the pediatric cases of nutritionally variant streptococcal endocarditis published in the English literature since 1971.