Percutaneous balloon mitral valvuloplasty (PBMV) was successfully performed in 50 selected patients with mitral stenosis by using Inoue pillow-shaped balloon and Inoue technique. The average diameter of balloon used was 26.9 +/- 0.9 mm. 90% (45/50) of cases had either double or single mitral commissura split. Of the rest 5 cases, 1 had a mitral score 13 and 4 had a history of mitral valve commissurotomy. Totally they had a mean mitral valve area increase from 1.13 +/- 0.32 to 2.21 +/- 0.43 cm2, left atrial pressure decrease from 31.8 +/- 9.3 to 14.7 +/- 5.6 mmHg, left atrial diameter reduction from 44.9 +/- 7.7 to 37.4 +/- 4.9 mm, and transmitral gradient decrease from 21.7 +/- 9.8 to 4.0 +/- 5.2 mmHg. Most patients had a obvious cardiac function improvement, especially in patients with mitral score of 8 or less. 30% patients (15/50) had a mild mitral regurgitation, but relieved 3-6 months after procedure. During one year of follow up, the majority of patients (16/20) were found in a good cardiac function, mitral area and the left atrial diameter, except in 4 patients with a high mitral score of more than 10. It is suggested that for patient with lower mitral morphological score and good general health, a larger diameter balloon might be suitable for effectively improving patient's symptom, but for patients with a previous surgical mitral commissurotomy, PBMV should not be selected.