To assess relative merits of the double and single (Inoue) balloon techniques of percutaneous balloon mitral valvuloplasty for treating symptomatic mitral stenosis, 33 patients who underwent dilatation with the double balloon were compared retrospectively with 28 who underwent dilatation with the Inoue balloon. There were no baseline differences in mean left atrial pressure, mean mitral gradient, or calculated mitral valve area between the two groups. The procedure was successful in 89% of patients in the double balloon group and in 93% in the Inoue balloon group. Final mitral valve area and absolute increase in mitral valve area were significantly greater in the double balloon group, in which there was a nonsignificant trend toward greater incidence of acute complications. Final left atrial pressure and mitral gradient were not different. Both techniques are useful and safe.