The hemodynamic effects of nifedipine in 15 patients with pulmonary hypertension (PH) secondary to congenital heart disease (CHD) were evaluated. The basal hemodynamic parameters were obtained before medication. The parameters were also obtained 60 minutes and 2 months after taking nifedipine. After treatment, PAPs were decreased 18% and 15% (P less than 0.01), PAPd 21% and 24% (P less than 0.01), PAPm both 19% (P less than 0.01), respectively. TPR were reduced 33% and 30% (P less than 0.01). SAP decreased slightly after 60 minutes. HR, CO and CI remained unchanged. Of the 10 patients suffering from hyperkinetic PH, 8 patients underwent closure of defects after treatment of nifedipine. The above results suggest that nifedipine is effective for patients with PH secondary to CHD. It acted as an antihypertensive agent in patients with CDH associated with hyperkinetic PH before operation.