New technologies are being introduced every day in the perioperative setting and perioperative practitioners will need to become increasingly familiar with transoesophageal echocardiography (TOE). TOE is used as a diagnostic tool during cardiac surgery in the operating theatre to direct the surgical procedure and to detect acute complications. TOE is also used to monitor cardiac function in patients undergoing non-cardiac surgery and in the intensive care unit (ICU) (Figure 1). The use of TOE is increasing in the cardiac catheterisation laboratory for percutaneous transcatheter procedures such as patent foramen ovale (PFO) closure, atrial septal defect (ASD) closure, aortic and mitral valvuloplasty, aortic valve implantation and mitral valve repair. Since the oesophagus is located directly behind the heart, TOE provides better image quality than transthoracic imaging for the assessment of posterior cardiac structures such as the mitral valve, left atrium and pulmonary veins.