Cardiac tamponade should be considered in a critically ill patient in whom the cause of haemodynamic shock is unclear. When considering tamponade, transthoracic echocardiography plays an essential role and is the initial investigation of choice. Diagnostic sensitivity of transthoracic echocardiography is dependent on image quality, and in some cases a transoesophageal approach may be required to confirm the diagnosis. Knowledge of the pathophysiology and echocardiographic features of cardiac tamponade are essential for the practicing Intensivist. This review presents an approach to the recognition, diagnosis, and treatment of cardiac tamponade in critically ill patients.