Shock is a rare complication of massive pleural effusion and few cases have been described in the literature. Massive pleural effusion can cause right ventricular collapse due to transfer of pressure from the pleura to the pericardial space, creating a medical emergency requiring thoracocentesis for evacuation. We describe the case of a man with submassive right pleural effusion seen in the pneumology unit of our hospital. During the admission process, he suffered arterial hypotension and cardiorespiratory arrest requiring orotracheal intubation and mechanical ventilation. Massive pleural effusion with mediastinal displacement could be seen on a chest film. Symptoms resolved after thoracocentesis to evacuate the space and tubes were removed 24 hours after the event.