Mitral valve (MV) dilation was first developed for adults and adolescents with rheumatic MV disease. It was then extended to children with congenital mitral stenosis (MS). Congenital MS is a morphologically heterogeneous lesion that generally affects both the valvar and subvalvar tension apparatus of the MV. Subtypes of congenital MS include “typical” congenital MS (which consists of thickened leaflets, short or absent chordae tendineae, obliteration of interchordal spaces, and two separate but often closely spaced papillary muscles), supravalvar mitral ring, parachute MV, and double-orifice MV. In many patients, there are features of multiple MS subtypes. Commonly associated lesions include other left heart obstructive anomalies (e.g., coarctation of the aorta, valvar or subvalvar aortic stenosis) and/or a VSD.