Percutaneous transvenous mitral commissurotomy (PTMC) is the therapy of choice for patients with mitral stenosis who are candidates for commissurotomy. PTMC also offers palliative therapy for patients who are not good surgical candidates. Patients with thin, pliable valve leaflets and little subvalvular disease are the best suited. Significant thrombus in the left atrium is a strong relative contraindication. PTMC with the Inoue balloon is technically easier to perform than is conventional balloon valvotomy and is better tolerated by most patients. During this procedure, the Inoue balloon is positioned against the mitral valve; it is repeatedly inflated at increasing balloon diameters until the transmitral valve gradient is sufficiently relieved. PTMC affords marked symptomatic improvement in most patients who undergo the procedure.