Percutaneous pulmonary valvulotomy (PPV) is the treatment of choice for isolated congenital pulmonary stenosis of infancy. However, experience with this technique in the adult is much more limited. From November 1983 to November 1990, PPV was performed in 10 adults in our Institute. The mean age was 40 +/- 19 years (range 21 to 71 years). Before PPV, 4 patients were in functional Class II and 6 in functional Class III of the NYHA classification. All procedures were successful with no complications. The right ventricular systolic pressure decreased from 98 +/- 35 to 57 +/- 30 mmHg (p less than 0.01) and the mean pulmonary gradient decreased from 57 +/- 30 to 23 +/- 15 mmHg (p less than 0.01). The cardiac output was unchanged: 5.3 +/- 2.8 and 5.9 +/- 2.6 l/mn (not significant). Pulmonary valve area increased from 0.59 +/- 0.3 to 1.15 +/- 0.5 cm2 (p less than 0.01). The post-dilatation infundibular gradient was less than 10 mmHg in all patients. After an mean follow-up period of 29 +/- 26 months all but one patient (Class II) were in functional Class I. Exercise capacity was 6.9 +/- 2 Mets. Doppler echocardiography indicated a stable mean pulmonary gradient of 16.5 +/- 6.8 mmHg after PPV and 15.0 +/- 7.0 mmHg during follow-up. Pulmonary regurgitation was less than Grade I in all cases. In conclusion, PPV is an effective treatment for adult pulmonary stenosis and carries a low risk. The mid term results are excellent.