An atypical presentation of purulent pericarditis caused by Staphylococcus aureus is described. A bacterial etiology was initially not taken into consideration because the clinical course was torpid and afebrile. Therefore, the appropriate treatment was delayed. The patient recovered after percutaneous pericardial drainage of his purulent pericardial effusion and antimicrobial therapy. The importance of a high index of suspicion of a bacterial cause in patients with pericardial effusion of unexplained etiology is emphasized.