The authors report 12 cases of metastatic pericardial effusions with clinical manifestations. Primary bronchial cancer is the most frequent with 7 cases; in 3 of these patients, the original manifestation is a tamponade. The contributions of sonocardiography to the diagnosis are analyzed: evaluation of hemodynamic tolerance and visualization within the effusion, in 4 out of 7 patients undergoing bidimensional sonocardiography, of dense masses, implanted on the visceral layer of the pericardium; the frequent epicardic location of these metastases may be explained by preferential invasion of the visceral layer by retrograde lymphatic route. The advantage of pericardial cytology is discussed. From the therapeutic standpoint, a pleuro-pericardial window or tetracycline instillation tend to prevent a recurrence of the effusion and the risk of tamponade; the neoplastic process is controlled with local and/or general chemotherapy and radiotherapy; therapeutic strategy depends on the sensitivity of the primary tumor. The prognosis remains very dim with a mean survival of 3.7 months in our series.