The purpose of this study was to demonstrate the utility and feasibility of transesophageal echocardiography during percutaneous balloon mitral valvuloplasty (PBMV). 40 patients were included with symptomatic rheumatic mitral valve stenosis with mean age of 31 years. Transoesophageal echocardiographic monitoring allowed an immediate detection of mitral insufficiency in 10 patients. This latter was moderate in eight cases and severe in two cases indicating to stop the procedure. The addition of on-line TEE during PBMV facilitate and confirm the success of the procedure and detect complications.