2-D & 3-D Trans-oesophageal Echocardiogram (TEE) Trans-oesophageal echocardiography (TEE) is an invasive procedure like endoscopy where a long slender probe (like a camera) is gradually introduced per-mouth and placed into the feeding tube behind the heart. This probe then emits sound waves that are then reflected from the heart to create an image on the monitor. Being very close to the heart TEE produces excellent images with enhanced resolution that often helps in delineating structures which would other-wise not be visible by an echocardiogram done from chest. The most important application of TEE in pediatric cardiology is intra-operative and post-operative assessment of a congenital heart disease as well as valvular heart disease. It requires a great deal of skill and understanding of the cardiac anatomy to perform a per-operative TEE. Trans-oesophageal approach is also extremely useful for pre-procedural assessment atrial septal defects in adults as well as to rule out infective endocarditis. In the present era 3D-TEE is also available which helps immensely in planning of device closure of septal defects as well as para-valvar leaks. TEE can be performed with reliable safety in both adults and children. In co-operative adults and adolescents the procedure can safely be performed using local anaesthesia in the throat. But in apprehensive patients as well as in smaller children often short course intravenous sedation may be necessary. In experienced hands it is a safe procedure with excellent diagnostic yield.