We report the case of a 71-year-old woman who presented with persistent high fever and progressive weakness for 10 days. Klebsiella oxytoca infective endocarditis was diagnosed based on four sets of positive blood culture of K. oxytoca together with fluttering vegetation (0.6 cm in diameter x 1.3 cm long) on the base of the anterior mitral leaflet. The diagnosis was documented using transthoracic and transesophageal echocardiograms. After 4 weeks of intravenous cefazolin therapy, the patient completely recovered.