A congenital deficiency of factor VII and protein C was found in a 21-year-old female suffering from recurrent and progressive attacks of dyspnea and hemoptysis over the last four years. She has been followed in our Department since the age of 17 under a diagnosis of peripheral pulmonary artery stenosis and pulmonary hypertension as confirmed by cardiac catheterization and angiography. Prolonged prothrombin time repeatedly examined during this time period prompted us to perform detailed coagulation studies. We found that factor VII and protein C were both half normal in activity as well as in antigen. Three other members of her immediate family were also found to be affected with this combined deficiency. Since the genes encoding factor VII and protein C are located in different chromosomes, the 13th and the second chromosomes, respectively, expression of the combined hereditary deficiency is a random and very rare association on the basis of frequencies of 1:50,000 for factor VII and 1:16,000 for protein C deficiencies.