In the antibiotic era, purulent pericarditis, an infection associated with high mortality, is uncommon. The causative organism is generally Staphylococcus aureus or Streptococcus pneumoniae arising from contiguous spread or hematogenous dissemination of an underlying infection elsewhere in the body. The present report describes a previously healthy individual who presented with acute infectious pericarditis with the offending organism identified as Lancefield group C Streptococcus equi. After an initial pericardial window was unable to prevent recurrent pericardial effusion, pericardiectomy was performed and the patient slowly recovered from the incident.