We report a new simplified method of mitral dilatation done on 146 patients. This technique use the Inoue balloon with progressive diameters under ultrasonographic control, avoiding the arterial part of the dilatation. The population include 9 pregnant women, 13 children, 13 with restenosis and closed heart and 12 restenosis after dilatation. Mean age is 32 +/- 16 years (9 to 72) and sex ratio 3.7 (114 F/32 M). Three groups are individualized according to histopathologic exam of mitral structure, group I (26%) concern good indication and III (32%) bad indication for this technique, group II (42%) contain intermediate indications. Commissurotomy increase the mean mitral square for 0.2 to 1.9 +/- 0.1 cm_. We observe 3 cases of chirurgical mitral insufficiency needing remplacement recruited for 2 patients from the group III. Mean fluoroscopic exposition time is 5.2 +/- 3.3 mn and procedure duration 18 +/- 11 mn. Hospitalisation duration is one day for 95% of the patients. This method remaining simple, efficient and safe permit a gain in time of 70% with a good comfort for patient and a return to work on the 4th day.