This study compared the results in 60 consecutive patients with severe rheumatic mitral stenosis, who underwent percutaneous double-balloon mitral valvuloplasty by means of a combination of 20 mm + 20 mm diameter balloon catheters (group A), with a similar group of 60 consecutive patients who underwent single (Inoue) balloon mitral valvuloplasty (group B). After balloon mitral valvuloplasty the hemodynamic measurements showed significant improvement in both groups: in groups A and B, respectively, mitral valve area calculated with the Gorlin formula increased from 0.9 +/- 0.2 to 2.1 +/- 0.5 cm2 (p < 0.001) and from 0.8 +/- 0.2 to 1.9 +/- 0.4 cm2 (P < 0.001). There was a significant improvement in cardiac functional status in both groups. There was no significant difference between the groups with regard to clinical or hemodynamic improvement, technical failure rate, inadequacy of dilatation, or complications. However, the double-balloon technique was more complex and involved a longer screening time-group A, 40 +/- 12 minutes; group B, 21 +/- 10 minutes (p < 0.001). In our institution the disposable supplies used for the Inoue balloon technique were 40% more expensive than those used for the double-balloon technique.