Purulent pericarditis is rarely the primary site of bacterial infection. It is usually a complication of an infection originating elsewhere in the body, arising by contiguous spread or haematogenous dissemination.This paper, however, describes a previously healthy young man, who developed a purulent streptococcal pericarditis with no localizable primary focus. Although many possibilities were investigated, the entry site of the pericarditis remains unknown.The incidence of purulent pericarditis has decreased considerably since the antibiotic era. It is typically an acute and potentially lethal disease, necessitating rapid diagnosis and adequate therapy to improve prognosis. Standard treatment combines appropriate antibiotic therapy with surgical drainage. However, the exact timing and type of surgery is still under discussion. Our patient was treated with antibiotics, subxiphoidal tube drainage of the pericardial fluid and intrapericardial thrombolysis. After three weeks, he developed tamponade, requiring partial pericardiectomy. He recovered completely and resumed his normal activities after a two-month hospitalisation.