Thorax x-rays were reviewed in 18 patients with portal hypertension. In 28% of these we found radiologic signs of pulmonary hypertension of the precapillary type. The existing relation between primary pulmonary hypertension and portal hypertension has been established in different scientific papers. In the published series the incidence of primary pulmonary hypertension is less than the one of found in these patients the physiopathology of this association is reviewed, and as a hypothetic manner it is postulated the possible roll of the hypoxaemia of the residents, at the altitude of the Bogota city. (2.640 mts) as a helping factor in this phenomenon.