ACTINOMYCOSIS is a progressive granulomatous disease with focal or systemic manifestations characterized by a tendency to produce multiple draining sinuses. 1 It is an uncommon infection, involving the heart in less than 2% of reported cases. 2 Heart disease is usually secondary to extension of primary thoracic actinomycosis. When the heart is involved, 42% of the patients have cardiac symptoms, with congestive heart failure predominating. 3 We present a case of actinomycotic purulent pericarditis and congestive heart failure in which the patient required pericardiectomy for restoration of normal cardiac function. Report of a Case A 51-year-old white woman was admitted with shortness of breath of two days' duration. She gave a history of low-grade temperature for the past two weeks and cough, nausea, and vomiting for the past four days. She was never hospitalized before except for tonsillectomy in early childhood. The patient was acutely ill, with shortness of breath;