Clinical, hemodynamic and operative findings of 125 children, up to the age of 12 years, were analysed to determine if the severity of pulmonary venous and arterial hypertension correlated with the severity of rheumatic mitral stenosis. Moderately severe to severe pulmonary venous and arterial hypertension was found in almost three-quarters of the patients. Operative findings indicated critical mitral stenosis in 69% of the cases. In India, following rheumatic fever, some patients follow an unusually rapid course in developing mitral stenosis severe enough to require operative treatment, even at the age of six years.