A group of 108 consecutive patients with moderate-to-severe pulmonic stenosis and intact ventricular septum, operated upon by means of a pump oxygenator between the years of 1957 and 1961, has been presented.The total mortality of the series was 2.77 per cent, and an additional 1.8 per cent were left with residual neurologic complications.Fifty per cent of the patients showed an excellent result as indicated by normal electrocardiograms or right ventricular pressure below 65 mm. Hg by cardiac catheterization. An additional 26 per cent had good resultsas indicated by the absence of symptoms, normal x-rays, mild electrocardiographic changes, and in three instances, slight right ventricular hypertension.Ten per cent had unsatisfactory results based on significant residual abnormalities in the electrocardiograms, x-rays, or postoperative catheterization data.