Purulent pericarditis is rarely encountered in the antibiotherapy era, mainly in immunosupressed patients, after cardiac operations, in septicemia. Diagnosis of purulent pericarditis is based upon the analysis of pericardial drainage, obtained through pericardiocentesis or preferably, through a surgical approach. The reported case has following peculiarities: clinical signs of false acute surgical abdomen; altered clinical and biological response to infection; Optimal treatment is early, efficient pericardial drainage, with low risk of tissue contamination and of pericardial constriction; Surgical subxyphoid pericardial drainage is prefered in patients with affected general status. Antero-(lateral) thoracic approach with associated anterior pericardiectomy ensures an efficient pericardial drainage and prevents pericardial constriction, with low risks for pleural contamination.