We report the case of a 50-year-old man admitted for cardiac tamponade. He was diagnosed with acute pneumonia. He had no previous medical history, but exhibited a body mass index of 41. Two days before admission, he complained of chest pain irradiating to the neck lateral side. Massive cardiac tamponade developed over 48 hours. There was no obvious cause for immunodepression. Pericardial puncture was ineffective, due to obesity and fluid high viscosity. Surgery was undertaken (Marfan intervention). Pericardial fluid was found to be purulent; direct examination revealed nocardia as bacteria with typical filamentous, branching rods. Despite adapted antibiotic treatment the patient died within a few hours. Acute pericarditis due to Nocardia is discussed.