Infective endocarditis (IE) is a multisystem disease that results from infection, usually bacterial, of the endocardial surface of the heart. The main causative organisms of IE are gram-positive streptococci, staphylococci, and enterococci Although Escherichia coli (E. coli) is among the most common causes of gram-negative bacteremia, IE due to this pathogen is rare. Here we report a case of a 68-year-old woman who presented with a 10-day history of fever and was diagnosed with IE according to Modified Duke Criteria. E. coli was isolated from her blood culture. On day two of admission, the patient developed an episode of atrial fibrillation. The patient was treated with intravenous cefotaxime 2g 8 hourly for six weeks, and made a complete recovery without any complications.